The Main Challenge
Your task is to arrive at the target number of 20 by adding together five numbers. You are limited to using digits 1 to 5 but these can be used any number of times in each calculation.
One way of making 20 is 4+4+4+4+4 (but you can write your answer as 44444 to save time). Can you list the other FIVE ways?
The 7puzzle Challenge
The playing board of the 7puzzle game is a 7-by-7 grid containing 49 different numbers, ranging from 2 up to 84.
The 5th & 7th rows contain the following fourteen numbers:
4 6 7 11 16 21 24 27 30 50 70 77 81 84
What is the sum of the multiples of 7?
The Lagrange Challenge
Lagrange’s Four-Square Theorem states that every positive integer can be made by adding up to four square numbers.
For example, 7 can be made by 2²+1²+1²+1² (or 4+1+1+1).
There are TWO ways of making 31 when using Lagrange’s Theorem. Can you find them both?
The Mathematically Possible Challenge
Using 2, 6 and 11 once each, with + – × ÷ available, which THREE numbers is it possible to make from the list below?
7 14 21 28 35 42 49 56 63 70
#7TimesTable
The Target Challenge
Can you arrive at 31 by inserting 1, 5, 6 and 6 into the gaps on each line?
- ◯×◯–◯×◯ = 31
- ◯²÷◯+◯²÷◯ = 31
- (◯÷◯+◯)×◯ = 31
Answers can be found here.
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