Decimal Operation Rules

How do you solve problems that involve adding decimals?

• Find the magic number

• Bring UP the decimal point

• Line up the decimals

• Completely ignore the decimal

How do you solve problems that involve subtracting decimals?

• Find the magic number

• Bring UP the decimal point

• Line up the decimals

• Completely ignore the decimal

How do you solve problems that involve multiplying decimals?

• Find the magic number

• Bring UP the decimal point

• Line up the decimals

• Completely ignore the decimal

How do you solve problems that involve dividing decimals?

• Find the magic number

• Bring UP the decimal point

• Line up the decimals

• Completely ignore the decimal

When multiplying decimals, how do you find the magic number?

• Count all the digits in the problem

• Count the digits behind the decimal in both factors.

• Line up the decimals

• Count the digits in front of the decimal in both factors.

What is the first step in solving a division decimal problem.

• Make the divisor a whole number

• Make the dividend a whole number

• Make sure the divisor is a decimal

What is the last step in solving a multiplication decimal problem?

• Bring the decimal down.

• Put the decimal back in using the magic number (count from the back)

• Put the decimal where you think it should go.

• Put the decimal back in using the magic number (count from the front)

In the following problem, what is the magic number?

4.32 * 0.006

• 2

• 3

• 5

• 7

In the problem, did they complete it correctly?

• Yes, this is correct.

• No, it is incorrect. They forgot to bring down the decimal.

• No, it is incorrect. They forgot to find the magic number and put the decimal back after solving.

Did the student solve this problem correctly?

• Yes, this is correct

• No, it is incorrect. They forgot to use the magic number.

• No, it is incorrect. They forgot to bring the decimal down.