Each light in this interactivity turns on according to a rule. What
happens when you enter different numbers? Can you find the smallest
number that lights up all four lights?
Investigate which numbers make these lights come on. What is the smallest number you can find that lights up all the lights?
Use the interactivities to complete these Venn diagrams.
A game in which players take it in turns to choose a number. Can you block your opponent?
Imagine a wheel with different markings painted on it at regular
intervals. Can you predict the colour of the 18th mark? The 100th
Use the interactivity to create some steady rhythms. How could you
create a rhythm which sounds the same forwards as it does
In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?
Starting with the number 180, take away 9 again and again, joining up the dots as you go. Watch out - don't join all the dots!
A game that tests your understanding of remainders.
If you have only four weights, where could you place them in order
to balance this equaliser?
A game for 2 or more people. Starting with 100, subratct a number from 1 to 9 from the total. You score for making an odd number, a number ending in 0 or a multiple of 6.
Can you find a relationship between the number of dots on the
circle and the number of steps that will ensure that all points are
Can you complete this jigsaw of the multiplication square?
A challenge that requires you to apply your knowledge of the
properties of numbers. Can you fill all the squares on the board?
Can you predict when you'll be clapping and when you'll be clicking
if you start this rhythm? How about when a friend begins a new
rhythm at the same time?
Does a graph of the triangular numbers cross a graph of the six
times table? If so, where? Will a graph of the square numbers cross
the times table too?
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
Investigate the smallest number of moves it takes to turn these
mats upside-down if you can only turn exactly three at a time.
The planet of Vuvv has seven moons. Can you work out how long it is
between each super-eclipse?
Arrange the four number cards on the grid, according to the rules,
to make a diagonal, vertical or horizontal line.
Given the products of diagonally opposite cells - can you complete this Sudoku?
In a square in which the houses are evenly spaced, numbers 3 and 10
are opposite each other. What is the smallest and what is the
largest possible number of houses in the square?
I am thinking of three sets of numbers less than 101. Can you find
all the numbers in each set from these clues?
Look at three 'next door neighbours' amongst the counting numbers. Add them together. What do you notice?
I am thinking of three sets of numbers less than 101. They are the
red set, the green set and the blue set. Can you find all the
numbers in the sets from these clues?
Nearly all of us have made table patterns on hundred squares, that
is 10 by 10 grids. This problem looks at the patterns on
differently sized square grids.
This package contains a collection of problems from the NRICH
website that could be suitable for students who have a good
understanding of Factors and Multiples and who feel ready to take
on some. . . .
A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.
What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?
What can you say about the values of n that make $7^n + 3^n$ a multiple of 10? Are there other pairs of integers between 1 and 10 which have similar properties?
Complete the magic square using the numbers 1 to 25 once each. Each
row, column and diagonal adds up to 65.
A student in a maths class was trying to get some information from
her teacher. She was given some clues and then the teacher ended by
saying, "Well, how old are they?"
Can you see how these factor-multiple chains work? Find the chain
which contains the smallest possible numbers. How about the largest
List any 3 numbers. It is always possible to find a subset of
adjacent numbers that add up to a multiple of 3. Can you explain
why and prove it?
What is the lowest number which always leaves a remainder of 1 when
divided by each of the numbers from 2 to 10?
For this challenge, you'll need to play Got It! Can you explain the
strategy for winning this game with any target?
Four of these clues are needed to find the chosen number on this
grid and four are true but do nothing to help in finding the
number. Can you sort out the clues and find the number?
Find some examples of pairs of numbers such that their sum is a
factor of their product. eg. 4 + 12 = 16 and 4 × 12 = 48 and
16 is a factor of 48.
How can you use just one weighing to find out which box contains
the lighter ten coins out of the ten boxes?
An environment which simulates working with Cuisenaire rods.
What is the smallest number with exactly 14 divisors?
The discs for this game are kept in a flat square box with a square
hole for each disc. Use the information to find out how many discs
of each colour there are in the box.
What is the value of the digit A in the sum below: [3(230 + A)]^2 =
Do you know a quick way to check if a number is a multiple of two?
How about three, four or six?
A game for 2 people using a pack of cards Turn over 2 cards and try
to make an odd number or a multiple of 3.
Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why?
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.
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
Can you find a way to identify times tables after they have been shifted up?