Chapter R - Review Exercises - Page 75: 42

$29$ marshmallows

Use the MDAS rule. The MDAS rule states that the order of operations will be: First Priority: Multiplication or Addition, which ever comes first from the left Next Priority: Addition or Subtraction, which ever comes first from the left Apply the MDAS rule to obtain: \begin{align*} &=3+8\div 2 - 3 \times 7 -4 +47 &\text{(Perform the multiplication first.)}\\ &=3+4-3\times 7-4+47 &\text{(Perform the division next.)}\\ &=3+4- 21 -4 +47 &\text{(Perform the multiplication.)}\\ &=7- 21 -4 +47 &\text{(Perform the addition.)}\\ &=-14 -4 +47 &\text{(Perform the subtraction.)}\\ &=-18 +47 &\text{(Perform the subtraction.)}\\ &=29 &\text{(Perform the addition.)}\\ \end{align*}