He labelled each bag with the number of coins inside it.
He could then pay any sum of money from 1 coin to 15 coins using one or more of the bags without opening any of the bags.
In this game players combine two given numbers to get as close to a target as possible using one of the operations: addition +, subtraction -, or multiplication ×, and each number once and only once. For example, combining (-3) and (-5) to get as close as possible to the target of […]
This is a game for two players, a group of 3 or 4 players, or for the whole class. You will need to download and cut out or otherwise make 2 sets of these 24 cards.
Separate the 40 number cards from the 8 operation cards and shuffle them separately to […]
In the TUG MUCH HARDER GAME you can add, subtract, multiply or divide the 2 scores (in either order). […]
A staircase has 12 steps. You can go down the steps one at a time or two at time.
You could go down 1 step, then 1 step, then 2 steps, then 2, 2, 1, 1, 1, 1 as in the picture.
In how many different ways […]
We need to use negative numbers for sub zero temperatures and for distances between the highest peaks on earth and the deepest points in the oceans and deep mines.
Mauna Kea’s summit is 4205 metres above sea level but it extends below the sea surface to a depth of -6000 metres. This makes Mauna Kea […]
Is it always possible, from any set of five positive whole numbers, to choose three numbers that add up to a multiple of 3?
For example, if you start with 4, 7, 11, 12 and 18, you can choose 4, 11 and 12 which add up to 27 (a multiple of 3).
The letters A, B, C, D, E, F, G and H correspond to the numbers from 0 to 7 with no repetitions.
Use the clues that A+C=A and F×D=F to find the values of two letters.
Use the clues A+H=E […]
You can mix the paints to produce different shades of pink. Explain how to find the ratio of […]
Try a few of these:
Do human beings live for as long as a million hours?
If you have been alive for a million seconds, how many birthdays have you had?
What year was it one billion minutes ago?
How long would it take to count to a million […]