What questions would you like to ask? What Do You Need? There are three tables in a room with blocks of chocolate on each. Multiply Multiples 1 Age 7 to 11 Challenge Level: There is a clock-face where the numbers have become all mixed up.

What do they mean? This dice train has been made using specific rules. Table Patterns Go Wild! What kind of number do you get? Four bags contain a large number of 1s, 3s, 5s and 7s. Age 5 to 7 Trial and Improvement at KS1 These lower primary tasks could all be tackled using a trial and improvement approach. What could my number be?

Mystery Matrix Age 7 to kw2 Challenge Level: Investigate the sum of the numbers on the top and bottom faces of a line of three dice.

This article, written for primary teachers, discusses what we mean by ‘problem-solving skills’ and draws attention to NRICH tasks which can help develop specific skills.

Can you use the information to find out which cards I have used?

## Addition and Subtraction KS2

How many pennies did Ram put in each bag? Ram divided 15 pennies among four small bags. Three Neighbours Age 7 to 11 Challenge Level: Can you compare these bars with each other and express their lengths as fractions of the black bar? On a digital clock showing 24 hour time, over hrich whole day, how many times does a 5 appear? Can you see how these factor-multiple chains work?

What Do You Need? How about the largest possible numbers?

All the Digits Age 7 to 11 Challenge Level: Can you prove it? What Do You Need? How many different shaped boxes can you design for 36 sweets in one layer?

Strike it Out Age 5 to 11 Challenge Level: Andy had a big bag of marbles but unfortunately the bottom of it split prbolem all the marbles spilled out. How many different ways can you do it? Each light in this interactivity turns on according to a rule. Play this game and see if you can figure out the computer’s chosen number.

Can you explain why this happens? How many extra pebbles are added each time?

## Problem-solving Skills

Ten cards are put into five envelopes so that there are two cards in each envelope. Register for our mailing list. Ordered Ways of Working Upper Primary These activities lend themselves to systematic working in the sense that it helps to have an ordered approach. Flashing Lights Age 7 to 11 Challenge Level: Use your prohlem and subtraction skills, combined with some strategic thinking, to beat your partner at this game.

How many ways can you find to do up all four buttons on my coat?

# Working Systematically at KS2 :

How many ways can you find to do up all four buttons on my coat? Fifteen Cards Age 7 to 11 Challenge Level: In this investigation we are going to count the number of 1s, 2s, 3s etc in numbers.

Age 5 to 7 Working Backwards at KS1 The lower primary tasks in this collection could each be solved by working backwards. Nearly all of us have made table patterns on hundred squares, that is 10 by 10 grids. Journeys in Numberland Age 7 to 11 Challenge Level: Play to 37 Age 7 to 11 Challenge Level: The tasks in this collection can be used to encourage children to convince others of their reasoning, using ‘because’ statements.