Calculate the formula according to the meaning of the question:
7+6- 10
=3 people
So there are three people in both competitions.
Subtraction calculation:
If you subtract a number from the sum of several numbers, you can choose any addend to subtract this number and add it to the rest of the addends. For example: (35+17+29)-25 = 35-25+17+29 = 56.
If you subtract several numbers from a number in succession, you can add all the subtractions first, and then subtract the sum of the subtractions from the minuend. For example: 276-115-85 = 276-(115+85) = 76.