Addition and subtraction

problem
Reach 100

Age

7 to 11

Challenge level

Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.
problem
One wasn't square

Age

7 to 11

Challenge level

Mrs Morgan, the class's teacher, pinned numbers onto the backs of three children. Use the information to find out what the three numbers were.
problem
Dividing a cake

Age

7 to 11

Challenge level

Annie cut this numbered cake into 3 pieces with 3 cuts so that the numbers on each piece added to the same total. Where were the cuts and what fraction of the whole cake was each piece?
problem
Routes 1 and 5

Age

5 to 7

Challenge level

Find your way through the grid starting at 2 and following these operations. What number do you end on?
problem
Four goodness' sake

Age

7 to 11

Challenge level

Use 4 four times with simple operations so that you get the answer 12. Can you make 15, 16 and 17 too?
problem
The tomato and the bean

Age

5 to 7

Challenge level

At the beginning of May, Tom put his tomato plant outside. On the same day he sowed a bean in another pot. When will the two be the same height?
problem
A-magical number maze

Age

7 to 11

Challenge level

This magic square has operations written in it, to make it into a maze. Start wherever you like, go through every cell and go out a total of 15!
problem
Spell by numbers

Age

7 to 11

Challenge level

Can you substitute numbers for the letters in these sums?
problem
Back to school

Age

7 to 11

Challenge level

Mr. Sunshine tells the children they will have 2 hours of homework. After several calculations, Harry says he hasn't got time to do this homework. Can you see where his reasoning is wrong?
problem
Oranges and lemons

Age

7 to 11

Challenge level

On the table there is a pile of oranges and lemons that weighs exactly one kilogram. Using the information, can you work out how many lemons there are?