What do you notice when you add opposite ends? If you have ten counters numbered 1 to 10, how many can you put into pairs that add to 10? Use these head, body and leg pieces to make Robot Monsters which are different heights. Find the Difference Age 5 to 7 Challenge Level: Age 5 to 7 Challenge Level: Can you find out where all the numbers have got to from these ten statements? These sixteen children are standing in four lines of four, one behind the other.

Countdown Age 7 to 14 Challenge Level: As you come down the ladders of the Tall Tower you collect useful spells. Secret Number Age 5 to 7 Challenge Level: Can you choose sets of numbers to collect so that you spin six numbers belonging to your sets in as few spins as possible? Annie and Ben are playing a game with a calculator. Can you do it in fewer throws of the dice? Find all the numbers that can be made by adding the dots on two dice.

Fifteen Cards Age 7 to 11 Challenge Level: Can you use the information to find out which cards I have used?

This project challenges you to work out the number of cubes hidden under a cloth. Growing Garlic Age 5 to 7 Challenge Level: In the second article, Jennie offers you practical ways to investigate aspects of your classroom culture and in the third article, she suggests three ways in which we can support children in becoming competent problem solvers.

Use five steps to count forwards or backwards in 1s or 10s to get to Junior Frogs Age 5 to 11 Challenge Level: Age 7 to 11 Challenge Level: Addition and Subtraction KS1.

Try grouping the dominoes in the ways described. Stop the Clock Age 5 to 7 Challenge Level: Shut the Box Age 5 to 7 Challenge Level: There is a clock-face where the numbers have become all mixed up. How could you put these three beads into bags?

Always, Sometimes or Never? This article suggests some ways of making sense of calculations involving positive and negative numbers. Addotion could the digit be?

What happens when you add three numbers together? They shared them out evenly and had one left over.

## Problem Solving

Cuisenaire Environment Age 5 to 11 Challenge Level: Can you stop your partner from being able to go? Can you match the cards?

Shopping – Pirate Poundland Age 3 to 5 Counting. How Do You Do It?

# Working Systematically at KS1 :

asdition Have a go at this well-known challenge. Use the interactivity to help you find out how many cloves of garlic they might have had. 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.

I’m Eight Age 5 to 11 Challenge Level: Play to 37 Age 7 to 11 Challenge Level: Can you explain why or why not? What happens when you add the digits of a number then multiply the result by 2 and you keep doing this?

Domino Sorting Age 5 ndich 7 Challenge Level: Can you complete this jigsaw of the square? Make 37 Age 7 to 14 Challenge Level: Ladybirds in the Garden Age 5 to 7 Challenge Level: Robot Monsters Age ;roblem to 7 Challenge Level: