The Main Challenge
Your task is to multiply two numbers together and then subtract a third number to achieve the target answer of 7. The three numbers used in each calculation must all be unique digits from 1-9.
For example, one such way of making 7 is (4×3)–5. Can you find SIX other ways to make 7?
[Note: (4×3)–5 = 7 and (3×4)–5 = 7 counts as ONE way.]
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 & 6th rows contain the following fourteen numbers:
5 6 7 12 16 18 20 21 33 49 50 56 81 84
What is the difference between the total of the prime numbers and the sum of the multiples of 10?
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 is only ONE way of making 15 when using Lagrange’s Theorem. Can you find it?
The Mathematically Possible Challenge
Using 5, 6 and 8 once each, with + – × ÷ available, which is the ONLY number it is possible to make from the list below?
5 10 15 20 25 30 35 40 45 50
#5TimesTable
The Target Challenge
Can you arrive at 15 by inserting 2, 3, 5 and 6 into the gaps on each line?
- ◯×◯+◯–◯ = 15
- ◯÷◯×◯²×◯ = 15
- ◯²–(◯+◯)×◯ = 15
Answers can be found here.
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