Addition operations

In this exercise, we propose the addition operation.

The first thing the student needs to know is how to align the terms of the operation correctly. For the terms of the addition to be correctly aligned, it must be :

• The units digit of the 2^th term is placed under the units digit of the 1^st term,
• the tens digit of the 2^th term is placed under the tens digit of the 1^st term,
• the hundreds digit of the 2^th term is placed under the hundreds digit of the 1^st term,
• and so on ...

In other words, the two terms of the addition must be aligned to the right.

For example, the operation

249 + 64

Correct positioning :

Incorrect positioning :

Next, calculate the sum column by column, starting from the rightmost column. In other words, add the units of the two terms and place the result in the units of the sum. :

9 + 4 = 13

If the sum of the two digits is greater than 9, then I add only the units digit to this column and retain the number 1 to add to the next column.

Now I add the tens digits of the two terms together with the number 1 (carry) :

4 + 6 + 1 = 11

Again, I add only the units to this column and retain the number 1 to add to the next column.

If a digit is missing, it is considered to be 0. And I have to add the carry 1 from the previous column. :

2 + 0 + 1 = 3