The order of operations - multiplication, addition, and subtraction only
In this 3rd grade lesson, we learn that multiplications are done before additions and subtractions. This lesson does not (yet) include parentheses or division (we will advance to include parentheses later). The purpose of these lessons is to prepare students for writing expressions for two-step word problems.
See also
Multiplication in two ways (multiplication is commutative)
Math Mammoth Grade 3 curriculum