How many times can you use?
3 + 5 =8
If you are only allowed to press the 1 and 0 keys on a calculator with any of the add, take, times, divide and equals keys, what is the fewest number of presses needed to make the number 9 on the calculator?
? + ? + ? + ? + ? = 30
You have to fill numbers in place of question marks. The numbers that you can use are 1, 3, 5, 7, 9, 11, 13 and 15. You can repeat the numbers if you like.