What is a Double in Math? Definition and Examples

What is a double in math? In math, a double can have either of the following two meanings:

• A multiplication in which any single number is multiplied the number 2

• An addition in which the two addends are the same number

For example, 8 + 8 is a double and 2 × 9 is also a double.

A couple of word problems about the meaning of double in math

Example #1

John has a yearly salary of 35,000 dollars. His goal is to double his salary after 5 years. What will be John salary after 5 years if he succeeds?

His salary will be 35,000 × 2 or 70,000 dollars

Example #2

Noemy has a 6 candies. His sister Sarah has the double of what Noemy has.  How many candies do they have together?

Sarah has 2 × 6 or 12 candies

Together, they have 6 + 12 or 18 candies