Addition and subtraction

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?
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

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

Penta Post

Age

7 to 11

Challenge level

Here are the prices for 1st and 2nd class mail within the UK. You have an unlimited number of each of these stamps. Which stamps would you need to post a parcel weighing 825g?
problem

The Clockmaker's Birthday Cake

Age

7 to 11

Challenge level

The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?
problem

Reverse Trick

Age

7 to 11

Challenge level

Tell your friends that you have a strange calculator that turns numbers backwards. What secret number do you have to enter to make 141 414 turn around?
problem

Sisters and Brothers

Age

7 to 11

Challenge level

Cassandra, David and Lachlan are brothers and sisters. They range in age between 1 year and 14 years. Can you figure out their exact ages from the clues?
problem

Clock Face

Age

7 to 11

Challenge level

Where can you draw a line on a clock face so that the numbers on both sides have the same total?
problem

Gift Stacks

Age

7 to 11

Challenge level

Use the information to work out how many gifts there are in each pile.
problem

Number Tracks

Age

7 to 11

Challenge level

Ben's class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?