1.1 & 1.2 Decimal Operations Study Guide Practice Activity

​Adding Decimals

• ​Line up decimals.

• ​Annex zeros (fill in empty places)

• ​Add the digits in the same place value position (regroup: carry) if necessary.

• ​Bring the decimal straight down into the sum (answer).

Multiple Choice

Try It! - Find the Sum:

42.46 + 10.44

• 529

• 5,290

• 5.290

• 52.90

​Subtracting Decimals

• ​Line up the decimals places.

• ​Annex (add) zeros has place holders.

• ​Subtract the digits in the same place value position (regroup: borrow) if necessary.

• ​​Bring the decimal straight down into the difference (answer).

Multiple Choice

Try It! - Find the difference:

$$902.3-8.8$$  

• 8,935

• 8.935

• 89.35

• 893.5

​Multiplying Decimals

• Multiply like whole numbers.

• Count the number of decimal places in each factor, then add them together.

• ​Shift the decimal point the total spaces counted from the factors. Place the decimal point in the product (answer).

Multiple Choice

Try It!: Choose the correct product below with the correct decimal placement.

• 3.25944

• 32.5944

• 325.944

• 3259.44

Multiple Choice

Try It! Find the Product:

$$12.5\ \times\ 163.2$$  

• 2.040

• 20.40

• 2,040

• 204.0

Multiple Choice

Try It! Find the Product:

$$5.05\ \times\ 3.1$$  

• 1.5655

• 15.655

• 15,655

• 156.55

Multiple Choice

Which number is the divisor in the problem?

$$1.08\ \div\ 0.027\ =\ 40$$  

• 1.08

• 0.027

• 40

​Dividing Whole Numbers

with Remainders in the Quotient.

• ​​Identify the dividend and divisor in your problem.

• ​Rewrite the division problem using the division house with the dividend under the "house".

• ​Divide normally (think: how many times the divisor can "fit into" the dividend without going over?) ---> Divide, Subtract, Bring Down, Repeat.

• If your remainder is smaller than the divisor and you have nothing else to bring down, write your remainder at the top of the division house next to the quotient.

Fill in the Blanks

What is the remainder when dividing...

$1,248\ \div\ 25$  

Type only the number in the text box.

​Divide Whole Numbers with Decimals in the Quotient.

• ​Identify the dividend and divisor in your problem.

• ​Rewrite the division problem using the division house with the dividend under the "house".

• ​Divide normally (think: how many times the divisor can "fit into" the dividend without going over?) ---> Divide, Subtract, Bring Down, Repeat.

• If your remainder is smaller than the divisor and you have nothing else to bring down, ​annex a zero when you run out of numbers to bring down.

• ​Bring down the number and repeat the division process.

• ​You should have a decimal in your quotient.

Multiple Choice

Try It! Find the Quotient with a decimal:

$$1,248\ \div\ 25$$  

• 4992

• 4.992

• 49.92

• 499.2

Multiple Choice

Try It! Find the Quotient:

$$120.4\ \div\ 602$$  

• 0.02

• 0.20

• 20

• 2

​Dividing Decimals with Decimals in the Dividend

• ​Identify the dividend and divisor in your problem.

• ​Rewrite the division problem using the division house with the dividend under the "house".

• ​Place a decimal point in the quotient by lining it up with the quotient.

• ​Divide normally (think: how many times the divisor can "fit into" the dividend.

​

Multiple Choice

Try It! Find the Quotient:

$$35.75\ \div\ 55$$  

• 65

• 6.5

• 650

• 0.65

​Dividing Decimals with Decimals in the Dividend and Divisor

• Rewrite the problem in the division house.

• ​STEP 1: Move the decimal point in the divisor to the far right of the divisor to make it a whole number.

• STEP 2: ​Move the decimal point the SAME NUMBER of places in the dividend.

• ​STEP 3: Write a decimal point in the quotient above the decimal point in the dividend.

• ​Divide as usual.

Multiple Choice

Try It! Find the Quotient:

$$48.4\ \div\ 0.4$$  

• 1.21

• 0.21

• 121

• 12.10