Copyright © University of Cambridge. All rights reserved.
'Largest Even' printed from http://nrich.maths.org/
I have a pile of nine digit cards numbered $1$ to $9$.
I take one of the cards. It is the $3$.
Which card would you choose so you could make the largest possible
two-digit even number with the two cards?
We put the cards back in the pile. This time, I choose the
$6$. Which card would you choose this time to make the largest
possible two-digit even number?
Have a go at this with a partner. One of you chooses the
first digit from the set of cards. The second person then
chooses a card to make the largest possible two-digit even number.
You can then swap over.
Try it several times so you are sure you have a good method. Talk
about your ideas with your partner so you agree together on a
How would your strategy change if you had to make the largest
two-digit odd number?
If you don't have a partner to work
with, you could use the interactivity below. The computer
selects one digit at random. You must then choose a
digit to make the largest possible two-digit even number or largest
possible two-digit odd number.