You may also like

problem icon

Double Digit

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?

problem icon

Number Detective

Follow the clues to find the mystery number.

problem icon

Six Is the Sum

What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?

Reach 100

Stage: 2 and 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Here is a grid of four "boxes":

Square divided into four.

You must choose four different digits from $1 - 9$ and put one in each box. For example:

Square divide into four, with 5,2,1 & 9 in the sections.

This gives four two-digit numbers:

$52$ (reading along the $1$st row)
$19$ (reading along the $2$nd row)
$51$ (reading down the left hand column)
$29$ (reading down the right hand column)

In this case their sum is $151$.

Try a few examples of your own.
Is there a quick way to tell if the total is going to be even or odd?

Your challenge is to find four different digits that give four two-digit numbers which add to a total of $100$.

How many ways can you find of doing it?

This problem is adapted from Make 200 from 'Mathematical Challenges for Able Pupils Key Stages 1 and 2', published by DfES.