# Resources tagged with: Multiplication & division

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There are 53 NRICH Mathematical resources connected to Multiplication & division, you may find related items under Calculations and Numerical Methods.

Broad Topics > Calculations and Numerical Methods > Multiplication & division

### Can You Make 100?

##### Age 11 to 14Challenge Level

How many ways can you find to put in operation signs (+ - x Ã·) to make 100?

### Going Round in Circles

##### Age 11 to 14Challenge Level

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

### Countdown Fractions

##### Age 11 to 16Challenge Level

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

### Countdown

##### Age 7 to 14Challenge Level

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

### The Remainders Game

##### Age 7 to 14Challenge Level

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

### Round and Round and Round

##### Age 11 to 14Challenge Level

Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 ÷ 360. How did this help?

##### Age 7 to 14Challenge Level

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

### Integrated Product Sudoku

##### Age 11 to 16Challenge Level

This Sudoku puzzle can be solved with the help of small clue-numbers on the border lines between pairs of neighbouring squares of the grid.

### More Magic Potting Sheds

##### Age 11 to 14Challenge Level

The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?

### Magic Potting Sheds

##### Age 11 to 14Challenge Level

Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?

### Product Sudoku

##### Age 11 to 16Challenge Level

The clues for this Sudoku are the product of the numbers in adjacent squares.

### Largest Product

##### Age 11 to 14Challenge Level

Which set of numbers that add to 10 have the largest product?

### Remainders

##### Age 7 to 14Challenge Level

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

### Number Rules - OK

##### Age 14 to 16Challenge Level

Can you produce convincing arguments that a selection of statements about numbers are true?

### Funny Factorisation

##### Age 11 to 16Challenge Level

Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?

### Expenses

##### Age 14 to 16Challenge Level

What is the largest number which, when divided into 1905, 2587, 3951, 7020 and 8725 in turn, leaves the same remainder each time?

### Legs Eleven

##### Age 11 to 14Challenge Level

Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?

### Charitable Pennies

##### Age 7 to 14Challenge Level

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

### Gabriel's Problem

##### Age 11 to 14Challenge Level

Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?

### So It's Times!

##### Age 7 to 14Challenge Level

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

### Escape from the Castle

##### Age 7 to 14Challenge Level

Skippy and Anna are locked in a room in a large castle. The key to that room, and all the other rooms, is a number. The numbers are locked away in a problem. Can you help them to get out?

### Missing Multipliers

##### Age 7 to 14Challenge Level

What is the smallest number of answers you need to reveal in order to work out the missing headers?

### 2010: A Year of Investigations

##### Age 5 to 14

This article for teachers suggests ideas for activities built around 10 and 2010.

### What Is the Question?

##### Age 11 to 16Challenge Level

These pictures and answers leave the viewer with the problem "What is the Question". Can you give the question and how the answer follows?

### Multiples Sudoku

##### Age 11 to 14Challenge Level

Each clue in this Sudoku is the product of the two numbers in adjacent cells.

### Galley Division

##### Age 14 to 16Challenge Level

Can you explain how Galley Division works?

### A First Product Sudoku

##### Age 7 to 14Challenge Level

Given the products of adjacent cells, can you complete this Sudoku?

### Alphabetti Sudoku

##### Age 11 to 16Challenge Level

This Sudoku requires you to do some working backwards before working forwards.

##### Age 11 to 14Challenge Level

If you take a three by three square on a 1-10 addition square and multiply the diagonally opposite numbers together, what is the difference between these products. Why?

### A One in Seven Chance

##### Age 11 to 14Challenge Level

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

### The Genie in the Jar

##### Age 11 to 14Challenge Level

This jar used to hold perfumed oil. It contained enough oil to fill granid silver bottles. Each bottle held enough to fill ozvik golden goblets and each goblet held enough to fill vaswik crystal. . . .

##### Age 11 to 14Challenge Level

Visitors to Earth from the distant planet of Zub-Zorna were amazed when they found out that when the digits in this multiplication were reversed, the answer was the same! Find a way to explain. . . .

### Why 8?

##### Age 11 to 14Challenge Level

Choose any four consecutive even numbers. Multiply the two middle numbers together. Multiply the first and last numbers. Now subtract your second answer from the first. Try it with your own. . . .

### Largest Number

##### Age 11 to 14Challenge Level

What is the largest number you can make using the three digits 2, 3 and 4 in any way you like, using any operations you like? You can only use each digit once.

### X Marks the Spot

##### Age 11 to 14Challenge Level

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" .

### Powerful Factorial

##### Age 11 to 14Challenge Level

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!?

### Eminit

##### Age 11 to 14Challenge Level

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?

### One O Five

##### Age 11 to 14Challenge Level

You can work out the number someone else is thinking of as follows. Ask a friend to think of any natural number less than 100. Then ask them to tell you the remainders when this number is divided by. . . .

### 3388

##### Age 11 to 14Challenge Level

Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.

### Slippy Numbers

##### Age 11 to 14Challenge Level

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.

### Factoring Factorials

##### Age 11 to 14Challenge Level

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

### Vedic Sutra - All from 9 and Last from 10

##### Age 14 to 16Challenge Level

Vedic Sutra is one of many ancient Indian sutras which involves a cross subtraction method. Can you give a good explanation of WHY it works?

### Two Many

##### Age 11 to 14Challenge Level

What is the least square number which commences with six two's?

### Ones Only

##### Age 11 to 14Challenge Level

Find the smallest whole number which, when mutiplied by 7, gives a product consisting entirely of ones.

### Times Right

##### Age 11 to 16Challenge Level

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?

### As Easy as 1,2,3

##### Age 11 to 14Challenge Level

When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type. . . .

### Thirty Six Exactly

##### Age 11 to 14Challenge Level

The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?

### Factorial

##### Age 14 to 16Challenge Level

How many zeros are there at the end of the number which is the product of first hundred positive integers?

### Oh! Hidden Inside?

##### Age 11 to 14Challenge Level

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

### Repeaters

##### Age 11 to 14Challenge Level

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.