Adding and Subtracting Positive and Negative Decimals

What is the first step in the algorithm for adding and subtracting decimals?

• Add placeholder zeros

• Bring the decimal straight down

• Line up the decimal points

• Determine whether to add or subtract absolute values

When adding or subtracting decimals, what should you do after lining up the decimal points?

• Move the decimal point

• Add placeholder zeros

• Add or subtract as usual

• Determine the final sign

In the first example, what is the result of -3.6 - 4.53?

• -8.13

• -7.93

• -8.03

• -7.83

What is the trick mentioned for handling double negatives?

• Subtract the smaller number from the larger one

• Add the absolute values

• Change minus minus to a plus

• Ignore the negatives

In the second example, what is the result of -3.6 + 4.53?

• 1.13

• 0.93

• 1.03

• 0.83

When subtracting absolute values, what should you do if the result is negative?

• Ignore the negative sign

• Change the sign of the result

• Add the absolute values

• Borrow from the next digit

In the third example, what is the result of -2.57 + -3.64?

• -6.31

• -6.41

• -6.11

• -6.21

What is the final step in the algorithm for adding and subtracting decimals?

• Determine the final sign

• Bring the decimal straight down

• Add placeholder zeros

• Line up the decimal points

Why is it important to determine the final sign of the result?

• To avoid adding placeholder zeros

• To correctly represent the direction on the number line

• To simplify the calculation

• To ensure the answer is positive

What is the key takeaway from the lesson on adding and subtracting decimals with negatives?

• Use a number line for all calculations

• Determine the final sign and bring the decimal straight down

• Line up the decimal points

• Always add placeholder zeros