Whole Numbers

This section illustrates how to compute the addition, subtraction, multiplication and division of whole numbers.

Addition

Add the numbers 584 and 646.

Procedure: In addition, we add from right to left. So for the problem above, we start with the extreme right column. The numbers in that column are 6 and 4; when added 6 + 4 = 10, the zero is written below the line in the column (extreme right column) and the 1 (highlighted blue) is added to the numbers in the middle column. Next, the numbers in the middle column, 8 & 4, are added to 1(highlighted blue); 8 + 4 + 1 = 13. The 3 is written below the line in the middle column and the 1 (highlighted red) is added to the numbers in the left column. Lastly, the numbers in the left column, 5 & 6, are added to 1 (highlighted red); 5 + 6 + 1 = 12. The 12 is then written below the line. That is, 584 + 646 = 1230.

Subtraction

Subtract 342 from 864.

Procedure: When subtracting, subtract from right to left. For the problem above, start with the extreme right column. The numbers in that column are 4 & 2; 4 – 2 = 2, 2 is written below the line in the extreme right column. Next, subtract the numbers in the middle column; 6 – 4 = 2, 2 is written below the line in the middle column. Lastly, subtract the numbers in the left column; 8 – 3 = 5. 5 is written below the line in the left column.

Multiplication

Multiply 462 by 246.

Procedure: When multiplying, multiply the top number (in this case 462) by each of the numbers in the bottom number (in this case 246), starting with the number to the extreme right. The number to the extreme right in the bottom number is 6. On multiplying, 462 x 6 = 2772 is the result. 2772 is written below the line. Next, 462 is multiplied by 4: 462 x 4 = 1848, 0 is added to the right of 1848, resulting in 18480(the amount of zeros added is determined by the amount of numbers to the right of the number in the bottom row being used, in this case 1 number is to the right of 4 i.e. 6). 18480 is written below 2772. Next, 462 is multiplied by 2: 462 x 2 = 924, two zeros is then added to 924 (as there are two numbers to the right of 2 i.e. 4 & 6) resulting in, 92400. 92400 is then written below 18480. Lastly, 2772, 18480 and 92400 are added, equalling to 113652.

Division  

Divide 4350 by 5.

Procedure: Since 4 is not divisible by 5, zero (0) is written above 4. 43 is then divided by 5: 5 goes into 43, 8 times, 8 is above 3. 5 multiplied by 8 is 40, 40 is then subtracted from 43, which yields 3. 3 is not divisible by 5, and hence 5 is taken down (follow arrow) to make 35. 35 is then divided by 5, which yields 7. 7 is then written above 5: 7 multiplied 5 is 35, this 35 is then subtracted from 35, yielding 0. Lastly 0 is taken down (follow arrow). 0 divided by 5 is 0, o is therefore written above 0. So, 4350 divided 5 is 870.

Combining them altogether

The example below, is of a problem that combines the use of addition, subtract, multiplication and division.

Example

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