Addition and subtraction

Well now, what would happen if we lost all the nines in our number system? Have a go at writing the numbers out in this way and have a look at the multiplications table.

Sam got into an elevator. He went down five floors, up six floors, down seven floors, then got out on the second floor. On what floor did he get on?

In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?

When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type 'TWO' it returns 2, and so on.

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.

Move from the START to the FINISH by moving across or down to the next square. Can you find a route to make these totals?

This Sudoku requires you to do some working backwards before working forwards.

Suppose there is a train with 24 carriages which are going to be put together to make up some new trains. Can you find all the ways that this can be done?

Vera is shopping at a market with these coins in her purse. Which things could she give exactly the right amount for?