This is a puzzle provided by the ten-year-old grandson of one of our question setters, and it has amused us all. We hope you enjoy it as well. The puzzle was provided on a Post It note which we have recreated below.
All you have to do is make the equation written below correct with the addition of one straight line. However, you are not allowed to change the equals sign to a not-equals sign. Anything else goes!
The answer is to change one of the plus signs into a four, making (for example) this equation:
545 + 5 + 5 = 555