MENTAL ADDITION

Addition is easier than Subtraction. Here we find a way how to make addition even easier.

We can easily add, 63 + 9 = 72, but how would you add this in your mind?

That is, to add 10 to any number, 16 + 10 is 26, 28 + 10 is 38, etc.,

In Mental addition, the basic is – To Add 9, Add 10 and Subtract 1; To Add 8, Add 10 and Subtract 2; To Add 7, Add 10 and Subtract 3; and so on.

Then, if you want to Add 49, Add 50 and Subtract 1; To Add 198, Add 200 and Subtract 2.
This makes it easy to hold numbers in your mind.

For example- 25 + 8 = ?; 33 + 7 = ?; 56 + 6 = ?;

Simple Principle for Mental Addition

If the units digit is high, round off to the next ten and then subtract the difference. If the units digit is low, add the tens, then the units.

For example,
47 + 26 = ?; 33 + 15 = ?; 95 + 38 = ?; 47 + 84 = ?; 56 + 75 = ?

We can use the same method for adding three digit numbers. You may prefer to add from left to right; adding hundreds, then the tens, and then the units.

Ex: 345 + 243 = ?; 586 + 654 = ?; 796 + 159 = ?;

In Adding larger numbers, When adding a column of numbers, add pairs of digits to make tens first then add other digits.

Ex: 1) 1236 + 1587 + 4598 = ? ; 2) 4587 + 8796 + 6879 = ?

Mental Addition is easier than the effort of finding a pen and paper or calculator.