Moby practiced solving addition and subtraction problems, but he made some mistakes! Explain any errors you find, and include what the correct answer should be.

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities