Decimal Review
For this test, you will need to demonstrate your knowledge of decimals.

Place value will be tested. You should be familiar with how to write numbers in expanded and word
form. You will need to be able to match a picture of a grid to a decimal value, as well.

Comparing and ordering decimals will also be assessed. You will be asked to order decimals from least
to greatest and greatest to least. For example, order these decimals from least to greatest: 0.056;
0.4; 0.375; 0.92
You can watch this Khan Academy video to review comparing decimals.
http://www.khanacademy.org/math/arithmetic/decimals/decimal_place_value/v/comparing-decimals
There are several Khan Academy videos that review decimal concepts. Choose others that you think
might be helpful to you.

You should be familiar with fraction and decimal equivalents, like - .5=50/100 or .2 = 2/10=20/100

You will need to be able to add and subtract numbers that include decimals. Here are some hints.
Remember to line up the decimals and place values. Add “magic zeros” where and if needed. Bring
the decimal straight down into your answer. Add and subtract just like in a whole number problem.
Click here to review the steps and try a “workout” on your own:
http://www.math.com/school/subject1/lessons/S1U1L4GL.html#sm1
Here are a couple examples similar to the ones we worked in class:
2.05 + 3.4 + 5.126 = _______________
2.050
+ 3.400
5.126
10.576
or 6.7 – 4.31 = _________________
6.70
- 4.31
2.39

You will need to be able to round a number to the nearest designated place. Here’s an example and
some recommended steps to follow:
Round 3.42 to the nearest tenth.
Step 1. Underline the number in the tenths place, which is the 4.
Step 2. Look at the number to its right, which is the 2.
Step 3. Repeat the jingle “Five or more, raise the score. Four or less, let it rest.” That means add 1
to the underlined number (4) or leave the underlined number (4) alone by making no
changes to it. In this case, the 2 says, “Let the 4 rest.” There is no change to 4.
Step 4. To get a final answer, copy down the numbers to the left of and including the underlined
number. If the numbers to the right of the underline number are decimals, they should be
dropped. If the numbers to the right of the underlined number are whole numbers, they
should be turned to zeros and any decimals should be dropped.
Answer: 3.4
Here are more examples:
Round 3.489 to the nearest hundredth. (Underline the 8, look at the 9. Add 1 to 8 to get 9
and drop the 9 in the thousandths place) Answer: 3.49
Round 3.59 to the nearest one. (Underline the 3, look at the 5. Add 1 to 3 to get 4 and drop
.59) Answer: 4
Round 143.52 to the nearest ten. (Underline 4, look at the 3. Don’t change the 4.)
Answer: 140
Round 7.96 to the nearest tenth. (Underline 9, look at the 6. Add one to 9, which also adds
1 to 7.) Answer: 8.0 (the zero is kept here, because tenths was the desired place.)
Complete the place-value chart to find the value of each digit.
You can use a place-value chart to understand decimals. Whole numbers are to the left of the
decimal point. Decimals are to the right of the decimal point. The thousandths place is to the right of
the hundredths place.
The place value of the digit 6 in 1.726 is thousandths. The value of 6 in 1.726 is 6 X 1/1,000,
or 0.006.
Standard Form: 1.726
Word Form: one and seven hundred twenty-six thousandths
Expanded Form: 1 + 0.7 + 0.02 + 0.006