This article suggests some ways of making sense of calculations involving positive and negative numbers.

Different combinations of the weights available allow you to make different totals. Which totals can you make?

How can we help students make sense of addition and subtraction of negative numbers?

The picture shows a lighthouse and many underwater creatures. If you know the markings on the lighthouse are 1m apart, can you work out the distances between some of the different creatures?

In this game, you can add, subtract, multiply or divide the numbers on the dice. Which will you do so that you get to the end of the number line first?

Substitute -1, -2 or -3, into an algebraic expression and you'll get three results. Is it possible to tell in advance which of those three will be the largest ?

How many intersections do you expect from four straight lines ? Which three lines enclose a triangle with negative co-ordinates for every point ?

Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?

The idea of this game is to add or subtract the two numbers on the dice and cover the result on the grid, trying to get a line of three. Are there some numbers that are good to aim for?

In this game the winner is the first to complete a row of three. Are some squares easier to land on than others?

In this problem, we're investigating the number of steps we would climb up or down to get out of or into the swimming pool. How could you number the steps below the water?

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Number problems at primary level to work on with others.

First Connect Three game for an adult and child. Use the dice numbers and either addition or subtraction to get three numbers in a straight line.

Investigate different ways of making £5 at Charlie's bank.

Play this game to learn about adding and subtracting positive and negative numbers

Imagine a very strange bank account where you are only allowed to do two things...

The classic vector racing game brought to a screen near you.

What is the smallest number of answers you need to reveal in order to work out the missing headers?

In this article for teachers, Liz Woodham describes resources on NRICH that can help primary-aged children get to grips with negative numbers.

This article -useful for teachers and learners - gives a short account of the history of negative numbers.

Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?