Arithmetic sequences

Can you complete this jigsaw of the 100 square?

Can you complete this jigsaw of the multiplication square?

What can you say about the common difference of an AP where every term is prime?

How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?

Which of these pocket money systems would you rather have?

Can you describe what is happening as this program runs? Can you unpick the steps in the process?

What's the greatest number of sides a polygon on a dotty grid could have?

Reasoning about the number of matches needed to build squares that share their sides.

Katie and Will have some balloons. Will's balloon burst at exactly the same size as Katie's at the beginning of a puff. How many puffs had Will done before his balloon burst?