Explaining, convincing and proving

Are these statements always true, sometimes true or never true?

You'll need to know your number properties to win a game of Statement Snap...

The large rectangle is divided into a series of smaller quadrilaterals and triangles. Can you untangle what fractional part is represented by each of the shapes?

What is the greatest number of counters you can place on the grid below without four of them lying at the corners of a square?

Think of a number, square it and subtract your starting number. Is the number you're left with odd or even? How do the images help to explain this?

Which of these clues are needed to find the number? Which clues aren't helpful?

Can you put the numbers 1-5 in the V shape so that both 'arms' have the same total?

Investigate the sum of the numbers on the top and bottom faces of a line of three dice. What do you notice?

In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

This group activity will encourage you to compare different calculation strategies.