Fluently Adding, Subtracting, and Multiplying Decimals

This video tutorial covers the basics of adding, subtracting, and multiplying decimals. It begins with an introduction to the concepts, followed by detailed examples of addition and subtraction, including complex cases involving borrowing. The tutorial then moves on to combining weights using addition and concludes with a thorough explanation of multiplying decimals, emphasizing the correct placement of the decimal point.

What is the first step when adding or subtracting decimals?

• Convert decimals to fractions

• Align the numbers to the right

• Align the decimal points

• Add zeros to the end of the numbers

If Kim's time is 50.9 seconds and Martin's time is 0.26 seconds longer, what is Martin's time?

• 50.16 seconds

• 51.16 seconds

• 50.26 seconds

• 51.9 seconds

Katie finished a race in 20.442 seconds, which is 0.258 seconds faster than Amy. What was Amy's time?

• 20.442 seconds

• 20.258 seconds

• 20.7 seconds

• 20.184 seconds

Diego's suitcase weighs 45.64 pounds and his brother's weighs 58 pounds. What is the combined weight of their suitcases?

• 103.64 pounds

• 102.64 pounds

• 104.64 pounds

• 103.04 pounds

When multiplying decimals, what should you do with the decimal points initially?

• Ignore them

• Round them to the nearest whole number

• Align them

• Convert them to fractions

What is the area of a rectangle with length 3.25 and width 2.5?

• 7.25

• 8.25

• 8.125

• 7.125

How many decimal places should the product have if you multiply 3.25 by 2.5?

• 4

• 3

• 2

• 1

In the multiplication example, why do we add an invisible zero when starting a new row?

• To ensure proper place value

• To make the numbers even

• To align the decimal points

• To keep track of the carry-over

What is the area of an antique map with length 4.16 and width 2?

• 8.32

• 8.152

• 8.125

• 8.416

How many decimal places should the product have if you multiply 4.16 by 2?

• 2

• 1

• 3

• 4