Today’s Challenge
Read the following ten clues about a particular number:
- it’s less than 100,
- it’s one more than a multiple of 3,
- exactly one of its two digits is prime,
- you get a prime if you reverse its digits,
- it’s not a multiple of 5,
- it’s not a prime number,
- it has exactly four factors,
- it’s not a square number,
- the sum of its digits is prime,
- if you multiply it by 5, the answer is greater than 100.
Can you find the mystery number?
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 1st & 3rd rows of the playing board contain the following fourteen numbers:
2 9 13 14 15 22 25 36 40 42 45 66 72 80
How many multiples of 12 are on the list?
Make 99 Challenge
Can you arrive at 99 by inserting 2, 3, 5 and 9 into the gaps on each line?
- (◯×◯+◯)×◯ = 99
- ◯×◯×◯+◯² = 99
- (◯+◯)²+◯–◯² = 99
- ◯²×◯²–◯²÷◯ = 99
Answers can be found here.
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