List

Working backwards at KS2

Working backwards can be a very useful problem-solving skill.  These activities lend themselves to being tackled in this way.

This collection is one of our Primary Curriculum collections - tasks that are grouped by topic.

Nim-7
problem
Favourite

Nim-7

Age
5 to 11
Challenge level
filled star empty star empty star
Can you work out how to win this game of Nim? Does it matter if you go first or second?
Junior Frogs
problem

Junior frogs

Age
5 to 11
Challenge level
filled star filled star empty star
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Would You Rather?
problem
Favourite

Would you rather?

Age
7 to 11
Challenge level
filled star empty star empty star

Would you rather: Have 10% of £5 or 75% of 80p? Be given 60% of 2 pizzas or 26% of 5 pizzas?

Multiplication Squares
problem
Favourite

Multiplication squares

Age
7 to 11
Challenge level
filled star empty star empty star

Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

What's in the Box?
problem
Favourite

What's in the box?

Age
7 to 11
Challenge level
filled star empty star empty star

This big box multiplies anything that goes inside it by the same number. If you know the numbers that come out, what multiplication might be going on in the box?

First Connect Three
problem
Favourite

First connect three

Age
7 to 11
Challenge level
filled star empty star empty star
Add or subtract the two numbers on the spinners and try to complete a row of three. Are there some numbers that are good to aim for?
Nice or Nasty
problem
Favourite

Nice or nasty

Age
7 to 14
Challenge level
filled star empty star empty star
There are nasty versions of this dice game but we'll start with the nice ones...
missing multipliers
problem
Favourite

Missing multipliers

Age
7 to 14
Challenge level
filled star empty star empty star
What is the smallest number of answers you need to reveal in order to work out the missing headers?
Play to 37
problem
Favourite

Play to 37

Age
7 to 11
Challenge level
filled star empty star empty star
In this game for two players, the idea is to take it in turns to choose 1, 3, 5 or 7. The winner is the first to make the total 37.
Maze 100
problem
Favourite

Maze 100

Age
7 to 11
Challenge level
filled star filled star empty star
Can you go through this maze so that the numbers you pass add to exactly 100?
Mystery Matrix
problem
Favourite

Mystery matrix

Age
7 to 11
Challenge level
filled star filled star empty star
Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.
All the Digits
problem
Favourite

All the digits

Age
7 to 11
Challenge level
filled star filled star empty star

This multiplication uses each of the digits 0 - 9 once and once only. Using the information given, can you replace the stars in the calculation with figures?

Got It
problem
Favourite

Got it

Age
7 to 14
Challenge level
filled star filled star empty star

A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.

Andy's Marbles
problem
Favourite

Andy's marbles

Age
7 to 11
Challenge level
filled star filled star empty star

Andy had a big bag of marbles but unfortunately the bottom of it split and all the marbles spilled out. Use the information to find out how many there were in the bag originally.

Counting Cards
problem
Favourite

Counting cards

Age
7 to 11
Challenge level
filled star filled star filled star
A magician took a suit of thirteen cards and held them in his hand face down. Every card he revealed had the same value as the one he had just finished spelling. How did this work?