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Can you put these four calculations into order of difficulty? How did you decide?

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Can you match these calculation methods to their visual representations?

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It's Sahila's birthday and she is having a party. How could you answer these questions using a picture, with things, with numbers or symbols?

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This task combines spatial awareness with addition and multiplication.

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This challenge combines addition, multiplication, perseverance and even proof.

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Look at what happens when you take a number, square it and subtract your answer. What kind of number do you get? Can you prove it?

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This problem looks at how one example of your choice can show something about the general structure of multiplication.

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After training hard, these two children have improved their results. Can you work out the length or height of their first jumps?

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Here is a chance to play a version of the classic Countdown Game.

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Play this game and see if you can figure out the computer's chosen number.

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A group of children are using measuring cylinders but they lose the labels. Can you help relabel them?

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Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.

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In this game, you can add, subtract, multiply or divide the numbers on the dice. Which will you do so that you get to the end of the number line first?

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Annie and Ben are playing a game with a calculator. What was Annie's secret number?

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Find the product of the numbers on the routes from A to B. Which route has the smallest product? Which the largest?

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Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?

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Ahmed is making rods using different numbers of cubes. Which rod is twice the length of his first rod?

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The Man is much smaller than us. Can you use the picture of him next to a mug to estimate his height and how much tea he drinks?

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Here is a picnic that Petros and Michael are going to share equally. Can you tell us what each of them will have?

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There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

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Find out what a Deca Tree is and then work out how many leaves there will be after the woodcutter has cut off a trunk, a branch, a twig and a leaf.

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Use the information about Sally and her brother to find out how many children there are in the Brown family.

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I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?

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The value of the circle changes in each of the following problems. Can you discover its value in each problem?

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Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?

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Amy has a box containing domino pieces but she does not think it is a complete set. Which of her domino pieces are missing?

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On my calculator I divided one whole number by another whole number and got the answer 3.125. If the numbers are both under 50, what are they?

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During the third hour after midnight the hands on a clock point in the same direction (so one hand is over the top of the other). At what time, to the nearest second, does this happen?

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There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and lollypops for 7p in the sweet shop. What could each of the children buy with their money?

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We can arrange dots in a similar way to the 5 on a dice and they usually sit quite well into a rectangular shape. How many altogether in this 3 by 5? What happens for other sizes?

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Watch the video of this game being played. Can you work out the rules? Which dice totals are good to get, and why?

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In this simulation of a balance, you can drag numbers and parts of number sentences on to the trays. Have a play!

In this article for primary teachers, Ems outlines how we can encourage learners to be flexible in their approach to calculation, and why this is crucial.

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Investigate the different ways that fifteen schools could have given money in a charity fundraiser.

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Does this 'trick' for calculating multiples of 11 always work? Why or why not?

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Your vessel, the Starship Diophantus, has become damaged in deep space. Can you use your knowledge of times tables and some lightning reflexes to survive?

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How will you work out which numbers have been used to create this multiplication square?

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This task offers an opportunity to explore all sorts of number relationships, but particularly multiplication.

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Watch this animation. What do you notice? What happens when you try more or fewer cubes in a bundle?

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Can you find different ways of creating paths using these paving slabs?

Are you resilient enough to solve these number problems?

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Number problems at primary level that may require resilience.

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Number problems at primary level that require careful consideration.

This article for primary teachers encourages exploration of two fundamental ideas, exchange and 'unitising', which will help children become more fluent when calculating.

In this article, Alf outlines six activities using the Gattegno chart, which help to develop understanding of place value, multiplication and division.

In this article for primary teachers, Lynne McClure outlines what is meant by fluency in the context of number and explains how our selection of NRICH tasks can help.

Alf describes how the Gattegno chart helped a class of 7-9 year olds gain an awareness of place value and of the inverse relationship between multiplication and division.

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Four Go game for an adult and child. Will you be the first to have four numbers in a row on the number line?