Understanding Addition of Signed Decimals

The video tutorial explains how to add signed decimals, specifically fifteen point two and negative thirty-one point one. It covers the concept of absolute value, subtraction of decimals, and determining the sign of the sum. The tutorial also demonstrates the process on a number line, showing how the negative value outweighs the positive, resulting in a negative sum.

What is the initial observation about the sum of 15.2 and -31.1?

• The sum will be positive.

• The sum will be zero.

• The sum will be negative.

• The sum will be undefined.

What is the first step in adding signed decimals with different signs?

• Find the absolute values of the numbers.

• Add the numbers directly.

• Multiply the numbers.

• Ignore the signs of the numbers.

What is the absolute value of -31.1?

• -31.1

• 31.1

• 0

• 15.2

When subtracting decimals, what must be aligned?

• The signs

• The fractions

• The decimal points

• The whole numbers

What is the result of subtracting 15.2 from 31.1?

• 16.9

• 14.9

• 15.9

• 15.1

How is the sign of the sum determined?

• By the last number

• By the larger absolute value

• By the smaller absolute value

• By the first number

Why is the sum of 15.2 and -31.1 negative?

• Because both are positive

• Because both are negative

• Because -31.1 is larger

• Because 15.2 is larger

On a number line, where do you start to model 15.2?

• At -31.1

• At 0

• At 15.2

• At -15.2

How many units do you move left to represent adding -31.1?

• 15.2 units

• 46.3 units

• 31.1 units

• 0 units

What is the final position on the number line after adding 15.2 and -31.1?

• Positive 15.9

• Negative 31.1

• Negative 15.9

• Zero