Can you each work out the number on your card? What do you notice?
How could you sort the cards?
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?
This problem is designed to help children to learn, and to use, the two and three times tables.
Explore Alex's number plumber. What questions would you like to ask? Don't forget to keep visiting NRICH projects site for the latest developments and questions.
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.
48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?
56 406 is the product of two consecutive numbers. What are these
Use the information about Sally and her brother to find out how many children there are in the Brown family.
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
Can you complete this jigsaw of the multiplication square?
Can you find which shapes you need to put into the grid to make the
totals at the end of each row and the bottom of each column?
Choose a symbol to put into the number sentence.
This article for teachers describes how modelling number properties
involving multiplication using an array of objects not only allows
children to represent their thinking with concrete materials,. . . .
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?
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10
What is the lowest number which always leaves a remainder of 1 when
divided by each of the numbers from 2 to 10?
Work out Tom's number from the answers he gives his friend. He will
only answer 'yes' or 'no'.
Start by putting one million (1 000 000) into the display of your
calculator. Can you reduce this to 7 using just the 7 key and add,
subtract, multiply, divide and equals as many times as you like?
An old game but lots of arithmetic!
This big box multiplies anything that goes inside it by the same number. If you know the numbers that come out, what multiplication might be going on in the box?
Ahmed is making rods using different numbers of cubes. Which rod is twice the length of his first rod?
Can you put the numbers 1 to 8 into the circles so that the four
calculations are correct?
If the answer's 2010, what could the question be?
Imagine a pyramid which is built in square layers of small cubes. If we number the cubes from the top, starting with 1, can you picture which cubes are directly below this first cube?
Well now, what would happen if we lost all the nines in our number
system? Have a go at writing the numbers out in this way and have a
look at the multiplications table.
Shut the Box game for an adult and child. Can you turn over the cards which match the numbers on the dice?
Can you work out what a ziffle is on the planet Zargon?
Are these statements always true, sometimes true or never true?
Explore Alex's number plumber. What questions would you like to ask? What do you think is happening to the numbers?
Bernard Bagnall recommends some primary school problems which use
numbers from the environment around us, from clocks to house
In a Magic Square all the rows, columns and diagonals add to the 'Magic Constant'. How would you change the magic constant of this square?
Go through the maze, collecting and losing your money as you go.
Which route gives you the highest return? And the lowest?
Twizzle, a female giraffe, needs transporting to another zoo. Which
route will give the fastest journey?
Four Go game for an adult and child. Will you be the first to have four numbers in a row on the number line?
In this investigation, you are challenged to make mobile phone
numbers which are easy to remember. What happens if you make a
sequence adding 2 each time?
These sixteen children are standing in four lines of four, one behind the other. They are each holding a card with a number on it. Can you work out the missing numbers?
Here is a picnic that Petros and Michael are going to share equally. Can you tell us what each of them will have?
At the beginning of May Tom put his tomato plant outside. On the same day he sowed a bean in another pot. When will the two be the same height?
Using the statements, can you work out how many of each type of
rabbit there are in these pens?
If the numbers 5, 7 and 4 go into this function machine, what
numbers will come out?
A game for 2 people. Use your skills of addition, subtraction, multiplication and division to blast the asteroids.
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.
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?
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?
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?
Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.
Ben’s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?
A game for 2 or more players with a pack of cards. Practise your
skills of addition, subtraction, multiplication and division to hit
the target score.
Use your logical reasoning to work out how many cows and how many
sheep there are in each field.
This task combines spatial awareness with addition and multiplication.