Inverse operation 6+x=13

Theodore has 20 baseball cards. he sells of his cards to tom, of his cards to larry, and his mom accidentally throws away of his cards. how many baseball cards does theodore have left?

A stick l feet long is broken into two parts, one of which is twice as long as the other. How long is the shorter piece?

Peter is 25 years older than Chris. In 9 years, Peter will be twice as old as Chris is then. How old are peter and Chris.

A rectangular sandbox has a length of 5 and 1 thirds feet and a width of 3 and 3 fourth. what is the perimeter?

Whats the answer two 2x-3=1

If people blink about 13 times per minute, how many times do they blink in 7 hours?

Shawn made fudge brownies and peanut butter brownies. Each batch of fudge brownies makes 9 pans. Each batch of peanut butter brownies makes 7 pans. Shawn made 13 batches and ended up with 97 pans of brownies.

Twelve cubic inches of soda are left in a can that holds 20 cubic inches. What percent of the soda has been drunk? What percent of the soda is left in the can?

Is it true that (x+4) = x² + 16? Explain.

If AB = AD + DB and AD = AC, then AB = AC + DB because of the