This is a puzzle I love to play with my math students and I hope you will enjoy it too:
You are given the numbers 1, 2, 3, 4, and 5 exactly once.
Your target is a number, e.g. 36. Can you create a calculation with addition, subtraction, multiplication, division and parentheses, so that you arrive at this number?
Concatenating the numbers (like 12 out of 1 and 2) is explicitly forbidden.
For this example, the solution would be
$$ 36=(2+4) \cdot (1+5) $$
but remember: You can use each number only once.
Can you find a calculation for all numbers from 1 to 75?
BONUS question: Now powers are allowed! Can you go to 125 now?

