Make one big triangle so the numbers that touch on the small triangles add to There are three baskets, a brown one, a red one and a pink one, holding a total of 10 eggs. Number Lines Age 5 to 7 Challenge Level: Talk to your friends about how you work them out. Making Sticks Age 5 to 7 Challenge Level:

Age 5 to 11 Challenge Level: Two children made up a game as they walked along the garden paths. She arranged the cards into 6 unequal piles where each pile added to the same total. Can you explain why? Have a go at this game which involves throwing two dice and adding their totals. Double Trouble Age 3 to 5 Doubling numbers. In this game the winner is the first to complete a row of three.

There are three versions of this challenge. What happens with different starting numbers?

The sum of each side of the triangle should equal the number in addution centre. Can you use the information to find out when Kate was born? Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.

How could you arrange at least two dice in a stack so that the total of the visible spots is 18? Working Backwards at KS1.

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. Shut the Box Age 5 to 7 Challenge Level: KS1 Age 5 to 7 Challenge Level: This investigates one particular property of number by looking closely at an example of adding two odd numbers together. He could then pay any sum of money from 1p to 15p without opening any bag.

## Problem Solving

What are the secret jumps they make with their counters? As you come down the ladders of the Tall Tower you collect useful spells. This project challenges you to work eolving the number of cubes hidden under a cloth. Ladybirds in the Garden Age 5 to 7 Challenge Level: A game for two people, or play online.

# Working Backwards at KS1 :

Arrange three 1s, three 2s and three 3s in this square so that every row, column and diagonal adds to the same total. This is an adding game for two players. Doing and Undoing Age 5 to 11 Challenge Level: Can you find out where all the numbers have got to from these ten statements? Magic Vs Age 7 to 11 Challenge Level: Getting the Balance Age 5 to 7 Challenge Level: Secret Number Age 5 to 7 Challenge Level: What is the same?

Countdown Age 7 to 14 Challenge Level: Buzzy Bee Age 5 to 7 Challenge Level: Butterfly Flowers Age 5 to 7 Challenge Level: This challenge is about finding the difference between numbers which have the same tens digit.

Pat counts her sweets in different groups and both times she has some left over. Can you find out their scores?

# Addition and Subtraction KS2 :

Journeys in Numberland Age 7 to 11 Challenge Level: Use the number weights to find different ways of balancing the equaliser. Choose four of the numbers from 1 solvving 9 to put in the squares so that the differences between joined squares are odd. How quickly can you put back the numbers on the hundred square?