Raymond buys bottles of water at $2.10 each and a large pizza at $12.99. The total cost was $21.39. How many bottles of water b did he buy? Write an equation using the variable b use spaces before and after each math symbol.

Answer 1

2.10b + 12.99 = 21.39
b = 4

Sorry -- leaving spaces around the decimal points is ugly.
Maybe you should have said math operator.