1. What is the fewest number of pluses and minuses you need to do this?
Mathematics Puzzle 1 2 3 4 5 6 7 8 9 - +
Take the digits 1,2,3 up to 9 in numerical order and put either a plus sign or a minus sign or neither between the digits to make a sum that adds up to 100.
What is the fewest number of pluses and minuses you need to do this?

2. Mathematics Puzzle 1 2 3 4 5 6 7 8 9 - +
Example: = 100 I used 4 pluses and 2 minuses. (Total of 6 signs)

3. Click here to see the BBC Answer