 Hello and welcome to the session. In this session we are going to discuss how to compute the sum, difference, product and quotient of whole numbers. Let us start with the sum of whole numbers. To find the sum of two or more numbers, we add the numbers. For example, the sum of four and eleven is fifteen. Now let us see how to add whole numbers. To add whole numbers, we add the digits in each place value position starting from the unit place. For example, find the sum 231 plus 127. So here, we first write the number 231 and write the second number 127 just below the first number lining up the digits at the unit place. Now we shall add these two numbers. Now first we add the units that is 1 plus 7 and it is equal to 8. Now we add the digits at 10th place that is 3 plus 2 which is equal to 5 and now we add the digits at 100th place that is 2 plus 1 which is equal to 3. So we get the sum 358. Now we may need to regroup while adding. Find the sum 439 plus 184. So we write the first number that is 439 and write the second number 184 just below the first number lining up the digits at the unit place. Now we are going to add these two numbers. First we add the units that is 9 plus 4 and it is equal to 13 since it is a two digit number. So we write 3 at units place and place 1 above the 10th. Now we add the digits at 10th place that is 1 plus 3 plus 8 and this is equal to 12. Again it is a two digit number so we put 2 at 10th place and place 1 above the 100th. Now we add the digits at 100th place that is 1 plus 4 plus 1 which is equal to 6. So we get the sum as 623. Now we are going to discuss difference of numbers. To find the difference between two numbers we subtract the smaller number from larger number. For example difference between 4 and 11 is 11 minus 4 that is equal to 7. See here 11 is larger number and we subtracted the smaller number that is 4. Let us see how to subtract whole numbers. To subtract whole numbers we first line up the digits and then we subtract the digits in each place value position starting from the unit place. We may need to regroup the digits while subtracting. Let us consider an example. Find the difference 523 minus 46. First we line up the digits at the units place that is 523 minus 46. Now we start subtracting from units place. Since 6 is larger than 3 so we rename 3 as 13 and rename 2 at 10th place as 1. Now at units place we have 13 minus 6 which is equal to 7. Now we subtract the digits at 10th place since 4 is larger than 1 so we rename 1 as 11 and rename 5 at 100th place as 4. So 11 minus 4 is 7. Now we do not have any digit below 4 so we write 4 as it is at 100th place so we get 477 as answer that is 523 minus 46 is equal to 477. Now we are going to discuss product of whole numbers. The word product is used to represent the result of a multiplication. For example the product of 6 and 7 is 6 into 7 that is equal to 42. Now let us see how to multiply whole numbers. To multiply a whole number by a 1 digit whole number multiply from right to left and do regrouping if required. Let us take an example. Find the product 42 into 7. To find the product first we write 42. Now we place 7 at units place just below 42. Now we multiply starting from right side 7 into 2 is equal to 14. It is a 2 digit number so we place 4 at units place and we put 1 above at 10th place. Now 7 into 4 is equal to 28 and we add the 1 placed above so we get 28 plus 1 that is 29 so the product is 294. Now if we multiply a number with 2 or more digit number then we write individual products and then add. Let us take an example. Find the product 123 into 23 so we first write the number 123 and below it we write 23. So we start from right 3 into 3 is equal to 9 so at units place we write 9 then 3 into 2 that is 6. So at 10th place we write 6 and then 3 into 1 that is 3 so at 100th place we write 3. Now we multiply 123 by 2 we will write the obtained number below 369 starting from 10th place to remember it we place 0 or cross sign below the digit obtained at units place. So we have 2 into 3 that is 6 so we write below the 10th place of the above number 6. Now 2 into 2 is equal to 4 we write it below the 100th place of the above number and now 2 into 1 is equal to 2 so we write it at the 1000th place. Now we add the obtained numbers at units place we have 9 at 10th place 6 plus 6 is 12 so we write 2 at 10th place and write 1 above 3 that is 100th place. Now 1 plus 3 plus 4 is equal to 8 and at 1000th place we have 2 so now the product is 2829 so we write 123 into 23 is equal to 2829. Now let us discuss quotient of whole numbers the word quotient is used to represent the result of division. The number being divided is the dividend and the number we are dividing by is divisor. We should note that when dividing whole numbers divide in each place value position from left to right. Now let us divide the whole number 1468 by 32 so inside we write the dividend 1468 outside we write the divisor 32. Now we shall divide see 32 into 4 is 128 and 32 into 5 is 160 so 128 is less than 146 so we will take 4 in the quotient. So we write 128 below 146 and subtract. Now here we see that 8 is greater than 6 at units place so we replace 6 by 16 and at 10th place we replace 4 by 3. Now we have 16 minus 8 that is 8 at units place at 10th place we have 3 minus 2 that is 1. At 100th place we have 1 minus 1 that is 0 so 146 minus 128 is equal to 18 so this will be equal to 18. Now we bring down 8 and we have number 188. Now 32 into 5 is 160 and 32 into 6 is 192 since 160 is smaller than 188 so we take 5 in quotient and we write 160 below 188 and subtract. So here we get 8 minus 0 that is 8, 8 minus 6 is 2 and 1 minus 1 is 0 so we get 28. Now 28 is smaller than the divisor 32 so we cannot divide further and 28 is the remainder and in quotient we have 45. We should note that division by 0 is meaningless we say it is undefined. For example 7 divided by 0 is undefined and if we divide 0 by any number then the quotient is 0. That is 0 divided by 7 is equal to 0. Thus in this session we have discussed how to compute sum, difference, product and quotient of whole numbers. This completes our session hope you enjoyed this session.