The Ten Point Circle illustrates the pairs of numbers whose sum is 10.

Taking a further step, if you can notice, there are eight unique groups of three numbers that sum to 10.

1 + 2 + 7 = 10 is an example.

Below are the eight unique groups.

**What is the significance of this? Why should we remember this?**

When several numbers are added, then it becomes useful if we are able to get whole multiples of 10, i.e. 10, 20, 30, 40 and on on.

For example,

2 + 8 + 3 + 4 +3 + 2 + 5 + 3 = ?

In above sum,

- pair 2,8 adds to 10;
- group of 3, 4, 3 adds to 10;
- group of 2, 5, 3 adds to 10;

So, above sum becomes 10 + 10 + 10 = 30.

This can be extended to addition of larger numbers.

For example: 48 + 16 + 61 + 32 + 59 = ?

The above sum becomes simple with this method:

Right figure becomes: 10 + 10 + 6 = (2)6

Left figure becoes: 10 + 4 + 5 + 2(carry) = 21

So, above sum = 216

Let’s practice few more sums:

**a** 73 + 27 **b** 28 + 23 + 67 + 42 ** c** 31 + 33 + 57 + 69 + 54 + 16 **d** 49 + 31 + 69 + 21

**e** 55 + 65 **f** 18 + 72 + 33 **g** 38 + 33 + 42 + 28 + 22 ** h** 65 + 65