Try to group together numbers that are easier to add mentally before adding other numbers.
$110
Practice makes perfect
To find the total cost of the fishing trip using mental math, let's analyze the given information. First, we see that there are three different prices for three different age groups. Next, we should consider how many people of each group will be going on the fishing trip. Let's make a table. Remember to multiply the number of people going on the trip by the price per person.
Age Group
Price per Person
Number of People
Subtotals
Adults
$33
1
$33
Children
$25
2
$50
Seniors
$27
1
$27
To find the total price, we need to add all the subtotal prices together. To make our mental math a little easier, let's use the Commutative Property of Addition to group numbers together such that they are easy to add mentally. In this example, since we know 3+ 7=10, it's easier to mentally calculate 3 3+2 7 before adding 50.
33+50+27 ⇒ 3 3+2 7+50=110
The total cost of the deep-sea fishing trip for 1adult, 2children, and 1senior is $110.
