Place value

problem

Read This Page

Age

11 to 14

Challenge level

2 out of 3

Replace the letters with numbers to make the addition work out correctly. R E A D + T H I S = P A G E
problem

Spell by Numbers

Age

7 to 11

Challenge level

2 out of 3

Can you substitute numbers for the letters in these sums?
problem

Arrange the Digits

Age

11 to 14

Challenge level

2 out of 3

Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?
problem

Alien Counting

Age

7 to 11

Challenge level

2 out of 3

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

X Marks the Spot

Age

11 to 14

Challenge level

3 out of 3

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" .
problem

Back to Basics

Age

14 to 16

Challenge level

3 out of 3

Find b where 3723(base 10) = 123(base b).
problem

Just Repeat

Age

11 to 14

Challenge level

3 out of 3

Think of any three-digit number. Repeat the digits. The 6-digit number that you end up with is divisible by 91. Is this a coincidence?
problem

Three Times Seven

Age

11 to 14

Challenge level

3 out of 3

A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
problem

Two Spinners

Age

5 to 7

Challenge level

1 out of 3

What two-digit numbers can you make with these two dice? What can't you make?
problem

What Number?

Age

5 to 7

Challenge level

2 out of 3

I am less than 25. My ones digit is twice my tens digit. My digits add up to an even number.