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Resources tagged with Multiplication & division similar to Digital Roots:

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Broad Topics > Calculations and Numerical Methods > Multiplication & division

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Power Mad!

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.

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Repeaters

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594). Explain why whatever digits you choose the number will always be divisible by 7, 11 and 13.

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Remainders

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

I'm thinking of a number. When my number is divided by 5 the remainder is 4. When my number is divided by 3 the remainder is 2. Can you find my number?

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Skeleton

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Amazing as it may seem the three fives remaining in the following `skeleton' are sufficient to reconstruct the entire long division sum.

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Eminit

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

The number 8888...88M9999...99 is divisible by 7 and it starts with the digit 8 repeated 50 times and ends with the digit 9 repeated 50 times. What is the value of the digit M?

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Cows and Sheep

Stage: 2 Challenge Level: Challenge Level:1

Use your logical reasoning to work out how many cows and how many sheep there are in each field.

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Factoring Factorials

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Find the highest power of 11 that will divide into 1000! exactly.

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Sam's Quick Sum

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

What is the sum of all the three digit whole numbers?

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Times Right

Stage: 3 and 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Using the digits 1, 2, 3, 4, 5, 6, 7 and 8, mulitply a two two digit numbers are multiplied to give a four digit number, so that the expression is correct. How many different solutions can you find?

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Powerful Factorial

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?

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Slippy Numbers

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

The number 10112359550561797752808988764044943820224719 is called a 'slippy number' because, when the last digit 9 is moved to the front, the new number produced is the slippy number multiplied by 9.

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What Two ...?

Stage: 2 Short Challenge Level: Challenge Level:2 Challenge Level:2

56 406 is the product of two consecutive numbers. What are these two numbers?

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Method in Multiplying Madness?

Stage: 2 and 3 Challenge Level: Challenge Level:2 Challenge Level:2

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

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Four Goodness Sake

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Use 4 four times with simple operations so that you get the answer 12. Can you make 15, 16 and 17 too?

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The Deca Tree

Stage: 2 Challenge Level: Challenge Level:1

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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Zios and Zepts

Stage: 2 Challenge Level: Challenge Level:1

On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?

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Difficulties with Division

Stage: 1 and 2

This article for teachers looks at how teachers can use problems from the NRICH site to help them teach division.

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Napier's Bones

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?

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The 24 Game

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

There are over sixty different ways of making 24 by adding, subtracting, multiplying and dividing all four numbers 4, 6, 6 and 8 (using each number only once). How many can you find?

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Oh! Hidden Inside?

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Find the number which has 8 divisors, such that the product of the divisors is 331776.

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Divide it Out

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?

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Fair Feast

Stage: 2 Challenge Level: Challenge Level:1

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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Being Determined - Primary Number

Stage: 1 and 2 Challenge Level: Challenge Level:1

Number problems at primary level that may require determination.

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Multiply Multiples 1

Stage: 2 Challenge Level: Challenge Level:1

Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?

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A One in Seven Chance

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

What is the remainder when 2^{164}is divided by 7?

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Ordering Cards

Stage: 1 and 2 Challenge Level: Challenge Level:1

This problem is designed to help children to learn, and to use, the two and three times tables.

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Multiply Multiples 2

Stage: 2 Challenge Level: Challenge Level:1

Can you work out some different ways to balance this equation?

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Multiply Multiples 3

Stage: 2 Challenge Level: Challenge Level:1

Have a go at balancing this equation. Can you find different ways of doing it?

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Going Round in Circles

Stage: 3 Challenge Level: Challenge Level:1

Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?

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Factor-multiple Chains

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?

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All the Digits

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

This multiplication uses each of the digits 0 - 9 once and once only. Using the information given, can you replace the stars in the calculation with figures?

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So It's Times!

Stage: 2 and 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

How will you decide which way of flipping over and/or turning the grid will give you the highest total?

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Multiplication Squares

Stage: 2 Challenge Level: Challenge Level:1

Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

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Penta Post

Stage: 2 Challenge Level: Challenge Level:1

Here are the prices for 1st and 2nd class mail within the UK. You have an unlimited number of each of these stamps. Which stamps would you need to post a parcel weighing 825g?

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Curious Number

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Can you order the digits from 1-3 to make a number which is divisible by 3 so when the last digit is removed it becomes a 2-figure number divisible by 2, and so on?

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Highest and Lowest

Stage: 2 Challenge Level: Challenge Level:1

Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.

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Machines

Stage: 2 Challenge Level: Challenge Level:1

What is happening at each box in these machines?

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Practice Run

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Chandrika was practising a long distance run. Can you work out how long the race was from the information?

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Six Numbered Cubes

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

This task combines spatial awareness with addition and multiplication.

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Gift Stacks

Stage: 2 Challenge Level: Challenge Level:1

Use the information to work out how many gifts there are in each pile.

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Clever Santa

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

All the girls would like a puzzle each for Christmas and all the boys would like a book each. Solve the riddle to find out how many puzzles and books Santa left.

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Make 100

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Find at least one way to put in some operation signs (+ - x ÷) to make these digits come to 100.

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Division Rules

Stage: 2 Challenge Level: Challenge Level:1

This challenge encourages you to explore dividing a three-digit number by a single-digit number.

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What Is Ziffle?

Stage: 2 Challenge Level: Challenge Level:1

Can you work out what a ziffle is on the planet Zargon?

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Book Codes

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Look on the back of any modern book and you will find an ISBN code. Take this code and calculate this sum in the way shown. Can you see what the answers always have in common?

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Tom's Number

Stage: 2 Challenge Level: Challenge Level:1

Work out Tom's number from the answers he gives his friend. He will only answer 'yes' or 'no'.

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Pies

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Grandma found her pie balanced on the scale with two weights and a quarter of a pie. So how heavy was each pie?

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What's My Weight?

Stage: 2 Short Challenge Level: Challenge Level:1

There are four equal weights on one side of the scale and an apple on the other side. What can you say that is true about the apple and the weights from the picture?

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X Marks the Spot

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .

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Follow the Numbers

Stage: 2 Challenge Level: Challenge Level:1

What happens when you add the digits of a number then multiply the result by 2 and you keep doing this? You could try for different numbers and different rules.