Doubles and near doubles

Front

What is a double in addition?

Back

A double in addition refers to adding a number to itself, such as 5 + 5.

Front

What is a near double in addition?

Back

A near double is when you add a number to a number that is one more or one less than itself, such as 5 + 6 (which is a near double of 5 + 5).

Front

Calculate the double of 6.

Back

The double of 6 is 12 (6 + 6).

Front

If 5 + 5 = 10, what is 5 + 6?

Back

5 + 6 = 11, which is one more than the double of 5.

Front

What is the sum of 6 + 7?

Back

The sum of 6 + 7 is 13.

Front

How can you use doubles to solve 7 + 8?

Back

You can use the double of 7 (which is 14) and subtract 1 to find that 7 + 8 = 15.

Front

What is the result of 2 + 3?

Back

The result of 2 + 3 is 5.

Front

Explain how to use near doubles to add 7 + 8.

Back

You can think of 7 + 8 as 7 + 7 + 1, where 7 + 7 is a double (14) and then add 1 to get 15.

Front

What is the relationship between doubles and near doubles?

Back

Doubles are exact additions of the same number, while near doubles involve adding a number to a number that is one more or one less.

Front

If you know that 5 + 5 = 10, how can you quickly find 5 + 4?

Back

You can subtract 1 from the double: 10 - 1 = 9.