Exploring Multiplying Rational Numbers

This video tutorial covers the multiplication of rational numbers, including fractions and decimals. It explains the process of converting mixed numbers to improper fractions, cross-simplifying, and multiplying numerators and denominators. The tutorial also addresses multiplying decimals, emphasizing the importance of ignoring decimal points initially and adjusting them in the final answer. The video includes practice problems for both fractions and decimals, with a focus on checking the sign of the result using tricks like the 'good thing bad thing' method.

What is the first step when multiplying fractions?

• Find a common denominator

• Subtract the fractions

• Convert mixed numbers to improper fractions

• Add the fractions

Tags

CCSS.5.NF.B.6

When multiplying fractions, do you need a common denominator?

• Yes, always

• No, never

• No, only for adding and subtracting

• Yes, but only for mixed numbers

Tags

CCSS.5.NF.B.6

What should you do with the decimal point when multiplying decimals?

• Line it up with the other decimal point

• Move it to the left

• Move it to the right

• Ignore it until the end

Tags

CCSS.5.NBT.B.7

How do you determine the placement of the decimal point in the final answer when multiplying decimals?

• Count the total number of digits behind the decimal points in the problem

• Move the decimal point two places to the left

• Line up the decimal points before multiplying

• Move the decimal point two places to the right

Tags

CCSS.5.NBT.B.7

If you have an even number of negative signs in a multiplication problem, what will the sign of the answer be?

• Positive

• Negative

• Zero

• Undefined

Tags

CCSS.7.NS.A.2A

CCSS.7.NS.A.2B

In the problem 68.7 times -5, what is the correct placement of the decimal point in the final answer?

• One place to the right

• Two places to the right

• Two places to the left

• One place to the left

Tags

CCSS.7.NS.A.2A

When converting a mixed number to an improper fraction, what is the correct formula?

• Whole number times the denominator plus the numerator

• Numerator times the whole number plus the denominator

• Denominator times the whole number plus the numerator

• Whole number plus the numerator times the denominator

What is the result of multiplying -3 1/4 by 5/6?

• 65/24

• 3 1/4

• 13/4

• 5/6

Tags

CCSS.7.NS.A.2A

In the final example, what is the improper fraction form of 1 4/5?

• 5/4

• 4/5

• 5/9

• 9/5

What is the final simplified form of 99/10?

• 9 1/10

• 10 1/10

• 9 9/10

• 10 9/10