Adding and Subtracting Decimals

Front

What is the process for adding decimals?

Back

To add decimals, align the numbers by the decimal point, add the digits starting from the rightmost side, and carry over if necessary. Place the decimal point in the sum directly below the decimal points of the numbers being added.

Front

How do you subtract decimals?

Back

To subtract decimals, align the numbers by the decimal point, subtract the digits starting from the rightmost side, and borrow if necessary. Place the decimal point in the difference directly below the decimal points of the numbers being subtracted.

Front

What is the sum of 10.9, 8.6, and 12.4?

Back

The sum is 31.9 hours.

Front

What is the difference between 80.93 and 68?

Back

The difference is 12.93.

Front

If Kelly has $20 and spends $2.15 and $6.58, how much does she have left?

Back

Kelly has $11.27 left.

Front

What is the sum of 32.15 and 24.15?

Back

The sum is 56.30.

Front

What is the difference between the world record of 39.3 feet and Tamara's jump of 17.6 feet?

Back

The difference is 21.7 feet.

Front

Why is it important to align decimal points when adding or subtracting decimals?

Back

Aligning decimal points ensures that each digit is in the correct place value, which is crucial for accurate calculations.

Front

What is a common mistake when adding or subtracting decimals?

Back

A common mistake is misaligning the decimal points, which can lead to incorrect sums or differences.

Front

How can you check your work after adding or subtracting decimals?

Back

You can check your work by reversing the operation (e.g., if you added, subtract the sum from one of the original numbers) or by estimating the result.