Multiplication and division

problem
Favourite

Product Sudoku

Age

11 to 16

Challenge level

The clues for this Sudoku are the product of the numbers in adjacent squares.
problem
Favourite

Magic Potting Sheds

Age

11 to 16

Challenge level

Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?
problem
Favourite

More Magic Potting Sheds

Age

11 to 16

Challenge level

The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?
problem
Favourite

Expenses

Age

14 to 16

Challenge level

What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?
problem
Favourite

Number Rules - OK

Age

14 to 16

Challenge level

Can you produce convincing arguments that a selection of statements about numbers are true?
problem

Double Digit

Age

11 to 14

Challenge level

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?
problem

As Easy as 1,2,3

Age

11 to 14

Challenge level

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.
problem

Two Many

Age

11 to 14

Challenge level

What is the least square number which commences with six two's?
problem

Machines

Age

7 to 11

Challenge level

What is happening at each box in these machines?
problem

Interstellar

Age

11 to 14

Challenge level

What number could replace * so that */5 is between 3 and 4?