How could you sort the cards? Doing and Undoing Age 5 to 11 Challenge Level: Are there some numbers that are good to aim for? In Sam and Jill’s garden there are two sorts of ladybirds with 7 spots or 4 spots. 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:

Dotty Six Age 5 to 11 Challenge Level: Arrange three 1s, three 2s and three 3s in this square so that every row, column and diagonal adds to the same total. Magic Vs Age 7 to 11 Challenge Level: Sweets are given out to party-goers in a particular way. Teddy Town Age 5 to 14 Challenge Level:

Junior Frogs Age 5 to 11 Challenge Level: What numbers could be inside the envelopes? Totality Age 5 to 11 Challenge Level: These caterpillars have 16 parts. The upper primary tasks in this collection could each be solved by working backwards.

There are addifion baskets, a brown one, a red one and a pink one, holding a total of 10 eggs.

# Addition and Subtraction KS2 :

How does the total at the top change? Are some squares easier to land on than others?

Try out some calculations. This feature draws together tasks which give learners opportunities to reason ssolving different purposes. 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.

Annie and Ben are playing a game with a calculator. How many different triangles can you draw on the dotty grid which each have one dot in the middle?

# Calculations and Numerical Methods :: Addition & subtraction :

Number Pyramids Age 11 to 14 Challenge Level: Making Sense of Positives and Negatives Age 11 to 14 This article suggests some ways of making sense of calculations involving positive and negative numbers.

Can you find some paths of your own? Eggs in Baskets Age 5 to 7 Proglem Level: If you had a weight on the left-hand 7, where could you hang two weights on the right to make it balance? What numbers of total spots can you make? Adding and Subtracting Positive and Negative Numbers Age 11 to 14 How can we help students make sense of addition and subtraction of negative numbers?

He could then pay any sum of money from 1p to 15p without opening any bag. Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.

## Working Systematically at KS1

What questions would you like to ask? Additio you know the numbers that come out, what addition might be going on in the box?

Add the two numbers on the red dice and take away the number on the green. Tasks for KS1 children which focus on working systematically.

## Adding and Taking Away

These lower primary tasks could all be tackled using a trial and improvement approach. Nim-7 Age 5 to 14 Challenge Level: Are these statements relating to calculation and properties of shapes always true, sometimes true or never true? In how many different ways can they build their houses? Which totals can you make? What’s the smartest way to do it? What was Annie’s secret number? Doing and Undoing Age 5 to 11 Challenge Level: Can you explain adrition or why not?

Weights Age 11 to 14 Challenge Level: