Multiplication word problems

Multiplication word problems arise in situations where we do repeated addition of the same number. Think of multiplication as a shortcut for adding the same number multiple times.

You may need to study or review multiplication of whole numbers before proceeding with this lesson. Consider now the following word problems:

Interesting multiplication word problems

Problem #1:

An apartment has 4 bedrooms. Each bedroom has 3 bookcases. How many bookcases are there in the apartment?

Solution

Using addition, you can argue that there are 12 bookcases in the apartment since 3 + 3 + 3 + 3 = 12

However, the problem can also be solved a lot faster by doing a multiplication of 3 and 4 since 3 × 4 = 12

Multiplication always gives the same answer faster than repeated addition.

Problem #2:

There are 60 minutes in 1 hour. How many minutes are there in 12 hours?

Solution

Once again, you can use addition to solve this problem, but you will waste your time since you have to do repeated addition of 60 twelve times.

60+60+60+60+60+60+60+60+60+60+60+60 = 720

However, 60 × 12 = 720 gives you the same answer faster.

A detailed explanation on how to do the multiplication is shown below:

6 0
× 1 2
______
1 2 0
+ 6 0 0
_______
7 2 0

Problem #3:

Mr. John's new hybrid car gets him 50 miles per gallons. If Mr. John gets a full tank with 14 gallons of gas, How far can Mr. John go?

Solution

Number of miles = 50 × 14 = 700 miles.

A detailed explanation on how to do the multiplication is shown below:

5 0
× 1 4
______
2 0 0
+ 5 0 0
_______
7 0 0

Problem #4:

Sylvia's income from a full time job is 500 dollars per week. How much does Sylvia makes every year?

1 year = 52 weeks.

Thus, 500 × 52 = 26,000 dollars

A detailed explanation on how to do the multiplication is shown below:

5 0 0
× 5 2
_______
1 0 0 0
2 5 0 0 0
_________
2 6 0 0 0

Problem #5:

An investment of 1 million dollars yields 30000 every year. How much will the investment earn after 18 years?

After 18 years, the investment will earn 30000 × 18 = 540000 dollars.