It is important the students are practicing their math facts. The expectation for third grade is:
At least 80 correct out of 100 addition facts: 4 minutes (1st quarter/2nd quarter)
At least 80 correct out of 100 subtraction facts: 5 minutes (1st quarter/2nd quarter)
At least 80 correct out of 100 multiplication facts: 5 minutes (3rd quarter)
At least 80 correct out of 100 division facts: 5 minutes (4th quarter)
Here are some great sites for practicing timed math tests and fact games.