Triangular Numbers
Square Numbers
100

What is the 9th triangular number ?

45

100

What is the equation for the 6th square number ?

6 times 6 is 36

200

What are triangular numbers are 4th - 8th ?

10 ,15,21,28,36

200

What is the 4th square number ?

16

300

What is the 6th triangular number subtracted by the 5th ?

6

300

What simple method can you use to find a square number ?

Times the number by itself 

400

Why are they called triangular numbers?

Because they can be expressed graphically with triangular arrangements.

400

What is the 4th through 9th square numbers ?

16 , 25 , 36 , 49 , 64 , 81

500

`What position is 78 in?

12th

500

What is the 9th square number plus the 7th minus the 5th?

105