Mental calculations

There are 106 NRICH Mathematical resources connected to Mental calculations
Journeys in Numberland
problem
Favourite

Journeys in numberland

Age
7 to 11
Challenge level
filled star empty star empty star

Tom and Ben visited Numberland. Use the maps to work out the number of points each of their routes scores.

Number Round Up
problem
Favourite

Number round up

Age
5 to 7
Challenge level
filled star filled star filled star
Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.
missing multipliers
problem
Favourite

Missing multipliers

Age
7 to 14
Challenge level
filled star empty star empty star
What is the smallest number of answers you need to reveal in order to work out the missing headers?
One Big Triangle
problem
Favourite

One big triangle

Age
5 to 7
Challenge level
filled star empty star empty star

Make one big triangle so the numbers that touch on the small triangles add to 10.

Number Lines
problem
Favourite

Number lines

Age
5 to 7
Challenge level
filled star empty star empty star
A resource to try once children are familiar with number lines, and they have begun to use them for addition. It could be a good way to talk about subtraction. Leah and Tom each have a number line. Can you work out where their counters will land?
Can you Make 100?
problem
Favourite

Can you make 100?

Age
11 to 14
Challenge level
filled star empty star empty star
How many ways can you find to put in operation signs (+, −, ×, ÷) to make 100?
Magnifying glass
problem
Favourite

Number detective

Age
5 to 11
Challenge level
filled star empty star empty star

Follow the clues to find the mystery number.

Got It
problem
Favourite

Got it

Age
7 to 14
Challenge level
filled star filled star empty star

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.