Place value

problem
Two-digit targets

Age

5 to 7

Challenge level

You have a set of the digits from 0 to 9. Can you arrange these in the five boxes to make two-digit numbers as close to the targets as possible?
problem
Four-digit targets

Age

7 to 11

Challenge level

You have two sets of the digits 0-9. Can you arrange these in the five boxes to make four-digit numbers as close to the target numbers as possible?
problem
Balance power

Age

11 to 18

Challenge level

Using balancing scales what is the least number of weights needed to weigh all integer masses from 1 to 1000? Placing some of the weights in the same pan as the object how many are needed?
problem
One of thirty-six

Age

5 to 7

Challenge level

Can you find the chosen number from the grid using the clues?
problem
What do you need?

Age

7 to 11

Challenge level

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?
problem
Alien counting

Age

7 to 11

Challenge level

Investigate the different ways these aliens count in this challenge. You could start by thinking about how each of them would write our number 7.
problem
So many sums

Age

11 to 14

Challenge level

In this addition each letter stands for a different digit, with S standing for 3. What is the value of YxO?
problem
Back of the queue

Age

11 to 14

Challenge level

Weekly Problem 48 - 2013
What is the remainder when the number 743589 × 301647 is divided by 5?
problem
Diagonal sums

Age

7 to 14

Challenge level

In this 100 square, look at the green square which contains the numbers 2, 3, 12 and 13. What is the sum of the numbers that are diagonally opposite each other? What do you notice?
problem
One million to seven

Age

7 to 11

Challenge level

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?