Melody: That is fabulous Reinout-g, I liked your explanation too.
NEW PUZZLE
Rules:
You have to use some or all of the numbers to make the magic number. You are not allowed to use any of the numbers twice. (Unless one was written twice in the first place)
You can use brackets, +, -, x, or divide and that is it.
EASIER ONE
9,3,7,1 and the magic number is 66
HARD ONE
2,3,8,7,25,100 And the magic number is 387
Happy Calculations
Melody: Yes, very clever, I like Serena.
now lets see what we have.
Now for the divisability checks. What do we have so far?
1) We have Zamarronics's formula,
2) A number is exactly divisable by 10 if it has a zero at the end. (the last digit is zero)
3) A number is exactly divisable by 2 if it is even.
4) If a number is prime then it is only exactly divisable by 1 and itself
5) A number is exactly divisable by 5 if it ends in 0 or 5
6) A number is exactly divisable by 3 if the sum of its digits is exactly divisable by 3.
7) A number is exactly divisable by 9 if the sum of its digits is exactly divisable by 9
8) If the last 2 digits of a number are a multiple of 4, the whole number is exactly divisible by 4.
9) If the last 3 digits of a number are a multiple of 8, the whole number is exactly divisable by 8.
