### There are 17 results

Broad Topics >

Numbers and the Number System > Triangle numbers

##### Age 11 to 14 Challenge Level:

Here is a collection of puzzles about Sam's shop sent in by club
members. Perhaps you can make up more puzzles, find formulas or
find general methods.

##### Age 7 to 14 Challenge Level:

Sam displays cans in 3 triangular stacks. With the same number he could make one large triangular stack or stack them all in a square based pyramid. How many cans are there how were they arranged?

##### Age 11 to 14 Challenge Level:

Can you find an efficient method to work out how many handshakes
there would be if hundreds of people met?

##### Age 7 to 11 Challenge Level:

Complete the magic square using the numbers 1 to 25 once each. Each
row, column and diagonal adds up to 65.

##### Age 5 to 11 Challenge Level:

These alphabet bricks are painted in a special way. A is on one
brick, B on two bricks, and so on. How many bricks will be painted
by the time they have got to other letters of the alphabet?

##### Age 11 to 14 Challenge Level:

Take a look at the multiplication square. The first eleven triangle
numbers have been identified. Can you see a pattern? Does the
pattern continue?

##### Age 11 to 14 Challenge Level:

Triangular numbers can be represented by a triangular array of squares. What do you notice about the sum of identical triangle numbers?

##### Age 11 to 14 Challenge Level:

Can you describe this route to infinity? Where will the arrows take you next?

##### Age 7 to 11 Challenge Level:

Sam sets up displays of cat food in his shop in triangular stacks.
If Felix buys some, then how can Sam arrange the remaining cans in
triangular stacks?

##### Age 11 to 16 Challenge Level:

Take ten sticks in heaps any way you like. Make a new heap using one from each of the heaps. By repeating that process could the arrangement 7 - 1 - 1 - 1 ever turn up, except by starting with it?

##### Age 11 to 14 Challenge Level:

Can you find any two-digit numbers that satisfy all of these statements?

##### Age 7 to 11 Challenge Level:

Does a graph of the triangular numbers cross a graph of the six
times table? If so, where? Will a graph of the square numbers cross
the times table too?

##### Age 7 to 11 Challenge Level:

This activity creates an opportunity to explore all kinds of number-related patterns.

##### Age 11 to 14 Challenge Level:

Show that 8778, 10296 and 13530 are three triangular numbers and that they form a Pythagorean triple.

##### Age 11 to 14 Challenge Level:

Using your knowledge of the properties of numbers, can you fill all the squares on the board?

##### Age 11 to 14 Challenge Level:

I have forgotten the number of the combination of the lock on my
briefcase. I did have a method for remembering it...

##### Age 7 to 11 Challenge Level:

Each light in this interactivity turns on according to a rule. What happens when you enter different numbers? Can you find the smallest number that lights up all four lights?