This number riddle sounds like it needs a complicated calculation, but the answer is surprisingly simple. You need to place something between the digits 7 and 8 so the resulting number is larger than 7 but smaller than 8.
The trick is to think about decimals rather than arithmetic operations.
Answer: Put a decimal point between them to make 7.8.
The number 7.8 is greater than 7 and less than 8, so it satisfies both conditions perfectly. No multiplication, division or other symbol is needed.
This is a good example of a riddle where changing how you read the numbers is more important than doing any calculation.
