Page 171 - Start Up Mathematics_5

Triangular and Square Numbers

The numbers that can be arranged as dots in a triangular pattern are known as triangular
numbers.

1 1 + 2 = 3 1 + 2 + 3 = 6 1 + 2 + 3 + 4 = 10
So, 1, 3, 6, 10, … are triangular numbers.

Find the next two triangular numbers.

The numbers that can be arranged as dots in a square pattern are known as square numbers.

1 2 × 2 = 4 3 × 3 = 9 4 × 4 = 16

So, 1, 4, 9, 16, … are square numbers.
Find the next two square numbers.

1633
16