Add and Subtract with Significant Figures (1.6)

[peacewarriorangel]

Why can't my chemistry teacher be like you V_V

[Gorillasoh]

Hell yeah.

[polysuazo1]

thank uuuuu

[robertareys]

Very helpful ! Thank you.

[wrinklebulhata1]

Great explanation...thank u

[lemongrassmari]

Thank you!!

I don't know why I found it so hard to understand adding whole numbers and decimals, but now I get it. :)

[gabrielaw429]

@tdewitt451

if you are adding two numbers with different units, do you convert one of the numbers to match the units?

for example: 1.035m^2 + 42m = ?

[tdewitt451]

@gabrielaw429 you can't add or subtract two units with different units, so you have to convert. however, you can't make meters (m) and square meters (m^2) match, because they measure different things: meters measures length and square meters measures area. so honestly, there is no correct way to do that problem. however, it's totally fine to multiply or divide numbers with different units.

[xyoumakeitreal]

now that i understand i cant imagine why it was so hard to comprehend before lol. multiplication and division were a lot easier to me. thanks for the video!

[runescapetuneman32]

nice vid man help alot with my final tomorrow!

[alfonsopeterman]

Do you always line up the decimal point when dealing with significant figures???

[tdewitt451]

@alfonsopeterman only when you're doing addition and subtraction. the rules are different for multiplication and division, and i've got videos for those, too.

[Shininqbabe]

your awesome[:!

[MystyXsoul]

awesome vid :D

[XxjelsominoXx]

omg you soooooooooo gooodd thank uuuu :D

[italiaprincess777]

I love your videos:)

[celticsfanbeantown34]

what about 15.00 + 2.509. would you keep 2 after the decimal place?

[MystyXsoul]

@celticsfanbeantown34 yep ---> 17.50

[mrsal931224]

thanks



[iurmantoday]

Thank you

[maxieyellowbobpants]

thnk you thnk you thnk you!

[EllenMoment25]

i wish you taught at my school. My teacher is soooooo bad!

[MRvideoCONVERTER]

Life saver watched all your videos on sig figs from 1.1 to 1.6  all of which were wonderfully explained, thanks again

[rwr827]

Thank you!! This video is so great and the info is perfect!! You sir just saved my life

[Nohwri]

helped so much thank you :D

[LoverGothicGaaraKai]

this is so helpful! Thank you!!!

Now that I get it, it's super easy!!! :D

[danceforever95100]

Thank you so much :) Your videos explained everything my teacher tried to explain in a week . I totally understand this now :)

[Tomidog08]

Dude! Thank You so much! it took my teacher like 4 days to explain this, and you explained it in like 5 minutes

[Roxy4ureal]

thank you soo much!! I understand it alot better cause of your explanation. Wish you were my chemistry teacher, nd thanks to you i got a 90% on the test!!!

[Xyennirock01X]

i get it now thank you

[Xyennirock01X]

i love you u r my hero

[jvyl2007]

This made understanding soo much easier! My chem teacher didn't do a great job explaining, but now I totally get it!

[Flipflopsandsocks99]

thank you so much! all my chem teacher does is croak. she's like a thousand years old!

[1001crackers]

OHMYGOSH! thankyou!!! i wish i had you as my chemesty teacher, mine makes no sense, thanks again!:)

[amarsh85]

thanks alot man this really helpd!

[20mrh]

thank you! this helped a lot!

[OXSultanXO]

you are a live saver !! thank you for this series .

[allisonconehead]

SAVED MY LIFE

[connordd2]

2:33 Smiley Face!!!! Great, thanks for the help!

[raiden41x]

what if you are adding and multiplying in the same equation? what rule would you apply?

[loony109]

thanks!!! i agree that explaining this concept in words is quite difficult...however my teacher couldn't even demonstrated clearly OTL Your demo was crystal clear, you bet i'll be watching more of your videos when i don't get something!

[edgarhcardona]

how about adding whole numbers? why does 3420+2400+1095= 6900 

[nosaj2011]

"If the digit following the last digit to be retained is: 5, not followed by nonzero digit(s), and the preceding significant digit is even than the last digit should: stay the same." Example 78.65-------> 78.6 (because 6 is even)

Based on what my textbook says for the last problem you should keep the 8 leaving the answer as 14.8.

[tdewitt451]

@nosaj2011 yeah, some textbooks have that rule. find out if your teacher wants you to do that, and if they do, you should do it that way. the reason i don't teach that is because it's wrong, pure and simple. that method of rounding is known as the "banker's rule," and is used for accounting, you know, like calculating money in bank accounts, NOT for doing science. i have no idea when and why people started using it for scientific calculations, but there's no reason to use it for science.

[MrJessejconrad]

@tdewitt451 hey man, if you have an addition or subtraction problem that is in scientific notation such as -3.19e-3+7.45e-4.....do u count the decimal places when in this form or do u need to write it out like -.00319+.000745?

[tdewitt451]

@MrJessejconrad i answer this in my video called "scientific notation and significant figures (1.7)"

[yomyma2]

I love you!

[rawrheather]

Thanks so much! Now I can pass my physics quiz :)

[LunaTicTacs]

Thanks! I was having a lot of trouble with this, but your videos really helped. :b

[Soccerstar988]

Wow, thank you so much! I have a Chemistry quiz tomorrow, and my teacher isn't the best at being clear.

This completely helped me, and I understand!

[95stewartgirl]

You are awesome thanks to u im gona pass my chemistry quiz =D

[roxxyroll3r]

Also..for adding numbers less than 1, and that have a zero as the first number, for instance: 0.05 plus 5.405, would you still keep 2 decimal places? Or would you keep none because that first 0 to the right of the decimal isn't significant? HELP ):

[tdewitt451]

@roxxyroll3r yes, you keep both the 2 decimal places. don't worry about any numbers that are to the LEFT of the significant digits (those two zeros are to the LEFT of 5, which is the significant digit). you only worry about where the significant figure (the five) is, and that's in the second decimal place from the right. does that make sense?

[roxxyroll3r]

OK, you confused me on the last problem where you got 14. Wouldn't it be 13 since you're adding 8+5? also if you were to add 4.00 +6.001 +7.0, you would only keep ONE place to the right of the decimal in youre answer, right? B/c zero's to the right of the decimal which end the number are always significant? And for instance 0.00100 only has 3 sig figs because the first zero isnt sig, which makes the first two zero's to the right of the decimal also nonsig, am i right?

[tdewitt451]

@roxxyroll3r i'm not adding 8+5, i'm adding 8.679+0.3+5.88, so of course i get more than 13, i get 14.859. just type those three numbers into your calculator and that's the answer you'll get, you won't get 13. then you take that answer (14.859) and round it to one decimal point, so you get 14.9. if you have questions about significant zeros, watch my videos on those topics.

[roxxyroll3r]

@tdewitt451 Ahh, right. I understand now. I just was thrown off for some reason when you wrote the 14 first, followed by the decimals. Just made me think you were adding the 8 and the 5 BEFORE the rest. for some reason I didnt catch myself on that one haha. and yes, i've watched most of your videos now on scientific notation and sig figs. i have a much better understanding now. its just all a bit overwhelming at first, all the steps you have to do in all the different sig fig equation situations

[latinb3auty14]

I want a teacher like you! This helped sooo much, thanks :)

[tdewitt451]

@sophiesanguine absolutely!

[Cartier736]

Umm, if the smallest number of sig figs is (for example) 2. The would'nt the answer need to be rounded to having only two sig figs? Like if I have 81.257 + 3.2 = 84.457 shouldn't the answer after sig figs be 84 cause thats two significant figures as opposed to the answer being 84.5 according to your rule? Please help!

[tdewitt451]

@Cartier736 the rules for addition and subtraction are completely different from those for multiplication and division. i think you're confused because you're trying to take the rules you learned for multiplication and division and using them for this. the method i describe in this video is the standard way to use sig figs for addition and subtraction, so if it makes sense and you can do it yourself, you're all set.

[Cartier736]

@tdewitt451 Your right lol. my bad, thanx for the help, i totally understand now :D

[Mariss300ma]

You have no idea how much this helped!!!! :D

[spamneggs230]

what about whole numbers such as 1200 + 70? Which one has more decimal places?

[inotnotluvu]

Wow that helped ssssssooooooo much :) thank you!!!

[naturallysimi]

Ohh... that makes much more sense! thanks!

[ilikepaige]

Thank you so much! I have a quiz on sig figs & scientific notation tomorrow :)

[tazzenders]

@ilikepaige and i've one tomorrow!

[billionfriends]

THanks so much dude you're so much help!

[KingFaizon18]

thanks this helped me a lot!

[robotron50]

dude thank you for making your videos they are of great help to me :D

[JapanBreakfast]

Awesome video format. Nice work!

[CrawfishLover94]

why can't textbooks say this and just skip all the bullshit?

[abraham1998abe]

thanks really you the best bro

[NinjasxPwn]

Thank you sooo much... this was so helpful, WAY better than it explains in my textbook.

[DonJovieDoria]

tnx mate,you guys made me pass my exam :D

[TheAshwathi]

i wish u were my teacher!!

[JHogan78]

I wish I had seen your videos days ago... Old fart retaking old classes here and I'm now bald from pulling my hair out..

[ki6eki]

does it matter if you're changing the number into scientific notation?

[tdewitt451]

@ki6eki watch my videos on scientific notation and significant figures

[daniellybelly68]

your videos are amazing!!! thank you so much!

[13toesonthenose]

I can't believe I missed this on a test.. I am an Idiot!!!

[TheAhmedMAhmed]

that's virtually useful to anyone especially those who study scientific subjects

[DunWannaTellMyName]

you are an angel sent from heaven- thnx this rly helped

[2quints]

omg i wish u were my teacher

[salsa02]

thanks dude!!!

[sargonashoraia]

Thanks you sooooooooo much

[orchid1software]

thanks again perfect 

[KiddyBrucie15]

Do you happen to have a multi step video? For example combining multiplication/division with addition/subtraction? Those are the main problems that throw me off with sig figs.

[bgizzle68]

wut about adding and subtracting at the same time?

[tdewitt451]

@bgizzle68 same rules as for addition or subtraction separately, nothing different.

[r0ckstarferlife]

Thanks you so much for this video it was very helpful

[dhaccessories]

You are absolutely AMAZING. My teacher tried to explain this to me yesterday for a whole hour and I couldn't get it. Your video took less than 5 minutes now I completely understand. You are the Awesome!!!!!!!!

[luisdaa]

how would you use sig fig in a problem like this (squared root of (4.0021))?

[Kinin4]

So let me get this straight (now that I've worded it in my mind):

Sig Figging is..."supplemental"...to rounding? Like "Rounding, lvl. 2", or is it simply the in-depth rules of rounding?

[tdewitt451]

@Kinin4 great question! sig figging is the in-depth, jedi-master rules for rounding that you use if you're doing math for science questions. it's kind of like the rules for dressing well: plenty of people can put together some clothes that look nice (that's like regular rounding). but then you meet someone who's all like, "oh, if you're wearing that sort of a shirt, you really have to wear this color tie, etc. etc." that's like the sig fig rules--the special master rules for rounding in science.

[kazetsukai2]

@tdewitt451 God, you explained this better than my teacher. I thank you for that.

[Daltex951]

this is a great help

[songs0919]

My teacher did an example in class which I don't get at all. The problem was 620+25. I thought that the answer would be 645 because both numbers have 0 decimal places, but she said that the answer would be rounded to 650. I didn't understand why this was. Could you explain it?

[th4Guy77]

OMG THANK YOU THANK YOU THANK YOU THANKY YOU

I UNDERSTAND HOW TO DO THIS NOW

I NO LONGER CRY BECAUSE I DON'T GET THIS

[xxclipzzxx]

What if you have a number with no decimals like 20 0r 5

[RandomLinda14]

I GET IT NOW:)

Thank you so much for this video. I have been enlightened

Hopefully I'll pass my quiz tomorrow and do better:/

[wereluva]

haha you totally lost me when you explained how to add sig figs...i get it now!!!! thanks so much!! now i wont fail my chem 12 course LOL

[Msmmyeahmm]

YESSSSS I GET IT

[jejuliz]

yes- thank you so much. I've got a professor who (i can swear) only speaks Chinese (or at least it sounds like it) and I was getting SO frustrated in class earlier. At 27, i was embarrassed to keep asking questions, so these videos have been a great help. THANKS!!

[IbeJaleel]

@jejuliz I'm taking chem and bio for the first time in ten years, and in class I feel like fish out of water. But tedwitt451's videos help a great deal. We're on the same boat, so don't feel too bad. Good luck with your studies.

[jejuliz]

@IbeJaleel ha, yea! its been almost that long for me too! you too, good luck :) And, if you need any help with BIO, that's something I can do.

[rorror45]

my chemistry class goes so fast but anyway this video helps me a lot

thanks

[duckygoquack9944]

Thank you so much for your videos! I didn't understand this at all and I was afraid I was going to have to dropy chem accel to regular but I get it now! But could you please do a video about addition and subtraction using scientific notation but with different exponents? In my packet it says that if the exponents are different you must make them the same but it doesn't show how to do that and I'm very confused.

[Lauren5723]

So, in class, we had the problem: 7.945 + 82.3 So, the answer is 90.245, my line was drawn between the 2 and the 4. I looked at the for and saw that my 2 was to remain the same, so, I got the final answer of 90.2 According to my teacher however, the answer is 90.3 Because apparently, the 5 makes the 4 a 5, and then that 5 makes the 2 a 3. This seems different than what you taught..do you think that it's 90.2, or 90.3? Thank you!!

[tdewitt451]

@Lauren5723 i certainly don't want to start a rumble here, but you're absolutely right, and your teacher's wrong. when rounding, you look ONLY at the number just to right: in this case it's a 4, so you keep it 90.2. the fact there's a 5 two spaces away makes no difference whatsoever. consult another website if you want some more proof (type "how to round" into google), but you're correctly following the rules.

[Lauren5723]

@tdewitt451 Thank you so much by the way! I have found that my teacher constantly teaches wrong information, so I'm really trying to switch teachers. I have another question like this...the problem was "6.523 + 18.4 + 10" ..and the answer is "24.923" Once again, my teacher is saying that it would be 30 because the 9 makes the 4 a 5, and the 5 makes the 2 a 3. But I was thinking that it should be 30 because the 4 make the 2 stay the same and there can only be 1 sd because 10 has only 1 sd.

[cruzlc875]

@Lauren5723 WOW! that sux. I am learning this subject for chem. ANd your teacher is wrong. Hope you fixed that. Im sure you dont remember bc it was 9 months ago. lol