Decimal Computation

Addition

100

2.9 + 3.4

6.3

200

1.563 + 0.46

2.023

300

15.9 + 30.2 + 1.32

46.52

400

How do add two decimals who have different place values (1.31 + 0.003 ) 

You line up the two numbers by the decimal point and add them together. 

500

Gabby and Ximena both walk to Sylvester. Gabby's route is 2.6 miles long. Ximena's route is 2.8 miles long. 

How many miles total have they both walked? 

5.4 miles total.

Subtraction

100

14.1 - 3.6

10.5

200

3.21 - 1.365

1.845

300

3 - 0.003 - 0.0021

2.976

400

What should we do if our first number in a subtraction equation terminates at the hundredths place but our second number ends in the thousandths place? 

(12.12 - 4.342 ) 

Add the missing zeros behind the hundredths place and subtract. 

500

Sofia and Amanda each looked at a strand of their hair under a microscope and measured the diameter. Sofia's strand was 0.005cm in diameter and Amanda's Strand was 0.012cm in diameter.

How much greater was the diameter of Amanda's Hair?

0.007cm

Multiplication

100

0.1 x 0.1

0.01

200

15.3 x 1.34

20.502

300

1.0 x 1.22

1.22

400

Determine the strategy used to find the position of the decimal point after finding a product in a multiplication question. 

Counting the number of place values past to the right of the decimal point in every factor and moving the decimal point to the left that many times after finding the product.

500

Nicholas is measuring the area of a doormat. The length of the doormat is 3.65 feet in length and 9.0 feet in width. What is the total area of the doormat?

32.76 feet

Division

100

5 divided by 2.5

2

200

0.48 divided by 2

0.24

300

1.85 divided by .4

4.625

400

What is the place value of the smallest unit in the resulting number in 999.92 divided by 100?

the place value of the smallest unit is ten thousandths.

500

Abby is baking cookies and needs to divide a bag of chocolate chips into smaller portions. The bag contains 2.4 pounds of chocolate chips, and she wants to divide it into 6 equal portions for different recipes. How many pounds of chocolate chips will be in each portion? Estimate to the nearest tenth.

0.4 pounds

Decimal Facts

100

What are the first 4 place values to the right of the decimal point?

tenths, hundredths, thousandths, ten thousandths 

200

Counting decimal places are counted on what power?

Powers of 10 (base 10 system)

300

How do you convert a 0.345 into a fraction?

345/1000 or 69/200 when simplified 

400

How do we write 1 214/1000 as a decimal?

1.214

500

If we are multiplying two decimals, one ending on the hundredths place and another ending on the tenths place, we should move the decimal point how many units to the left in our resulting product?

3 units to the left