Bah, easiest is to break it up into 10's; from 25 x 25, you have a 25 x 10 (250), another 25 x 10 (250), and a 25 x 5 (125), add all 3 and you get... 625
@blumac81 Do the same for 125 please. And tell me if it is still easier. Different people find different things easier, i find multiplication easier than adding, so i prefer this method.
@mooseling1 Oh I agree, different people find different things easier, it all depends on if you're a visual, auditory, etc. learner. I meant no offense on the post, just pointing out there are other ways to do it. So anyway, 125 x 125 = (100 x 125) + (100 x 25) + (25 x 25) = 12500 + 2500 + 625 = 15625; I just segmented it down to 25's and 100's. Don't worry, I'm a Biology major at college so had to take a load of math.
@blumac81 I am very physics orientated so again have to do lots of maths. For me i like the sums i do to involve as little steps as possible, so when i see your method i have to admit i just cant follow :L For me personally, 53^2 - 51^2 is easier to do without pen/paper, than 18+46+23-17. Many people couldnt do the first sum, but i have a good understanding of a fast multiplication method for it and 2809 - 2601 is quite easy to do, but ask for 73-34 and i am slower than others in my class :L
@mooseling1 heh, I hear ya man, something about 6's that always trip me up, especially with numbers ending in 6 adding or subtracting 7 like 86 + 67 or whatever. Right now I'm working on dimensional analysis in chem and I'm lost on how the professor is teaching us to do it, so much easier to use simple division than orig/specific # x new unit/old unit = new # in new unit
let's try numbers that are close to 100 trick: 97^2=(97-3)*100(-3 cus it's 3 fewer than 100)+3^2(same reason) and you get 9409. 107^2=(107+7)*100(+7cus it's 7 more than 100) +7^2/same reason) and you get 11449.
@Meraj99 There is another fairly complicated way of doing it when it isnt ending in a five, but this is a simple trick (for me at least, how hard the concept is, and multiplying 70 X 80 in a few seconds in your head can be hard for some people) so i didnt put it up, because it would basically turn the video into a very boring maths lesson.
@Meraj99 What sum? If you really want to know how to say, square 56 then you take 50, and half it, and add whatever is left onto 25, so for 56, it would be 25+6=31, then when you have 31, you have 31-- so to get last two digits you simply sqaure 6, 6*6=36, so 56x56= 3136, for say 62, you do 25+12=37-- then 12x12=144, so that is 3844. That is for numbers in the 50's and then depending on how good your mental maths is in the 40's (take away from 25) and in 60's.
This is so much easier to calculate than it looks like.
35 * 35 = 1225 => 3 * 4 [12] [ 4 is the next number after 3 from 35] followed by 25 ... so 1225
25 * 25 = 625 => 2 * 3 [6] [3 is the next number after 2 from 25] followed by 25
75 * 75 = 5625 => 7 * 8 [56] followed by 25
125 * 125 = 15625 12 * 13 [156] followed by 25 [13 is the next number after 12 from 125]
145 * 145 = 21025 [14*15=210 - followed by 25 => 21025]
gigiontube 4 months ago
Bah, easiest is to break it up into 10's; from 25 x 25, you have a 25 x 10 (250), another 25 x 10 (250), and a 25 x 5 (125), add all 3 and you get... 625
blumac81 1 year ago
@blumac81 Do the same for 125 please. And tell me if it is still easier. Different people find different things easier, i find multiplication easier than adding, so i prefer this method.
mooseling1 1 year ago
@mooseling1 Oh I agree, different people find different things easier, it all depends on if you're a visual, auditory, etc. learner. I meant no offense on the post, just pointing out there are other ways to do it. So anyway, 125 x 125 = (100 x 125) + (100 x 25) + (25 x 25) = 12500 + 2500 + 625 = 15625; I just segmented it down to 25's and 100's. Don't worry, I'm a Biology major at college so had to take a load of math.
blumac81 1 year ago
@blumac81 I am very physics orientated so again have to do lots of maths. For me i like the sums i do to involve as little steps as possible, so when i see your method i have to admit i just cant follow :L For me personally, 53^2 - 51^2 is easier to do without pen/paper, than 18+46+23-17. Many people couldnt do the first sum, but i have a good understanding of a fast multiplication method for it and 2809 - 2601 is quite easy to do, but ask for 73-34 and i am slower than others in my class :L
mooseling1 1 year ago
@mooseling1 heh, I hear ya man, something about 6's that always trip me up, especially with numbers ending in 6 adding or subtracting 7 like 86 + 67 or whatever. Right now I'm working on dimensional analysis in chem and I'm lost on how the professor is teaching us to do it, so much easier to use simple division than orig/specific # x new unit/old unit = new # in new unit
blumac81 1 year ago
tell me how to do it the last number aint 5
Meraj99 1 year ago
let's try numbers that are close to 100 trick: 97^2=(97-3)*100(-3 cus it's 3 fewer than 100)+3^2(same reason) and you get 9409. 107^2=(107+7)*100(+7cus it's 7 more than 100) +7^2/same reason) and you get 11449.
woldemort78 1 year ago
@Meraj99 There is another fairly complicated way of doing it when it isnt ending in a five, but this is a simple trick (for me at least, how hard the concept is, and multiplying 70 X 80 in a few seconds in your head can be hard for some people) so i didnt put it up, because it would basically turn the video into a very boring maths lesson.
mooseling1 1 year ago
@mooseling1 LOL HAHA MY MATHS TEACHER GAVE THIS SAME SUM AS HOMEWORK LOL
Meraj99 1 year ago
@Meraj99 What sum? If you really want to know how to say, square 56 then you take 50, and half it, and add whatever is left onto 25, so for 56, it would be 25+6=31, then when you have 31, you have 31-- so to get last two digits you simply sqaure 6, 6*6=36, so 56x56= 3136, for say 62, you do 25+12=37-- then 12x12=144, so that is 3844. That is for numbers in the 50's and then depending on how good your mental maths is in the 40's (take away from 25) and in 60's.
mooseling1 1 year ago