Double
The term "double" means to multiply a given amount by 2. If we have 5 oranges, doubling 5 oranges gives us 10 oranges:
5 × 2 = 10
Double is also used to refer to an addition fact in which the two addends are the same number.
Examples
The following are all doubles:
5 + 5 = 10
11 + 11 = 22
37 + 37 = 74
This is essentially the same thing as multiplying by 2. We can think of doubling something as either adding the same number to itself, or multiplying by 2. The result will be the same.
Examples
Referencing the examples above:
5 × 2 = 5 + 5 = 10
11 × 2 = 11 + 11 = 22
37 × 2 = 37 + 37 = 74
The concept of doubling can be useful as a starting point for learning multiplication since it can be framed first in the context of addition. One way to look at multiplication is to frame it as adding groups of objects. If we have 1 group of 5 objects, and we multiply by 2, that means that we have 2 groups of 5 objects, which is equal to 5 + 5 objects, or 10. This works for other numbers as well, but starting with equally sized groups to demonstrate the concept can be helpful.
Example
If Carrie has double the amount of candy as Josh does, and Josh has 8 pieces of candy, how many pieces of candy does Carrie have?
8 × 2 = 16
If we double 8, we get 16, so Carrie has 16 pieces of candy, or 2 groups of 8.
Did you know??
Doubling an amount is the opposite of halving an amount. In the example above, Carrie has 16 pieces of candy. Josh has half the amount of candy as Carrie, which is 8 pieces.