Addition and Subtraction Try these activities which all involve addition and subtraction. How could you sort the cards? What numbers could be inside the envelopes? What are all the different possible answers? Investigate the total number of sweets received by people sitting in different positions. The Box Game Age 3 to 5 Adding and subtracting. Subtraction Surprise Age 7 to 14 Challenge Level:

Amy has a box containing domino pieces but she does not think it is a complete set. Are there any left over each time? What do you notice? The value of the circle changes in each of the following problems. Addition and Subtraction Try these activities which all involve addition and subtraction.

# Square Subtraction :

Strike it Out game for an adult and child. I’m thinking of a number.

Consecutive Numbers Age 7 to 14 Challenge Level: Investigate matrix models for complex numbers and quaternions. Number Balance Age 5 to 7 Challenge Level: Can you find some more examples?

# Kangaroo Subtraction :

Use the maps to work out the number of points each of their routes scores. This task combines spatial awareness with addition and multiplication.

Strike it Out game for an adult and child. Start with four numbers at the corners of a square and put the total of two corners in the middle of that side. Diving in at the Deep End Age 7 to 11 Subtracyion tasks in this group will give you the opportunity to create some proofs of your own.

Remainders Age 7 to 11 Challenge Level: Ten cards are put into five envelopes so that there are two cards in each envelope. Cuisenaire Environment Age 5 to 11 Challenge Level: Plenty of Pens Age 7 to 11 Challenge Level: Bernard Bagnall recommends some primary school problems which use numbers from the environment around us, from clocks to house numbers.

## Adding and Subtracting

How could you arrange at least two dice in a stack so that the total of the visible spots is 18? Given a target number, say 23, and a range of numbers to choose from, sayplayers take it in turns to add to the running total to hit their target. You are organising a school trip and you need to write a letter to parents to let them know about the day. Reverse the digits, so write your number back to front.

Games – Lower Primary Age 5 to 7 Playing these games will help to test your understanding of different topics. In this addition each letter stands for a different digit, with S standing for 3.

What do you notice? Diving in at the Deep End Age 7 to 11 The tasks in this group will give you the opportunity to create some proofs of your own. Butterfly Flowers Age 5 to 7 Challenge Level: Make one big triangle so the numbers that touch on the small triangles add to To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

Try out some calculations. What Could It Be? Try out this number trick. What was the total and sokving could this be done?

Read Lynne’s article which discusses the place of problem solving in the new curriculum and sets the scene. This addition sum uses all ten digits 0, 1, Leah and Tom each have a number line.

An investigation involving adding and subtracting sets of consecutive numbers.