Decimal Skills Review

Comparing and ordering decimal fractions

Writing Decimal Fractions

Decimals on a Number Line

Squaring numbers in your head

Squaring numbers in your head

Walter Hickey / BI

Squaring large numbers can be a real pain sometimes. But if you're plugging something into a formula, easy mental squaring could be a huge asset. 

So say you've got a number, x, that you want to square.

Find "d" the difference between the nearest multiple of ten and x.

Then, multiply (x-d) and (x+d). This should be much easier, because one of the numbers is a multiple of ten. Just add d2, and you've got your square. 

Here's an example. I want to find the square of 84. The nearest multiple of ten is 80, so d is 4. 

x+d is 88, x-d is 80. 

88 X 80 = 6400 + 640 = 7040. Add 42 = 16, and you get 7056.

That process, once you get the hang of it, is much easier than just attacking 842 head on.  



Read more: http://www.businessinsider.com/x-math-party-tricks-that-will-make-you-a-rockstar-2013-6?op=1

Understanding decimals.

Source*: Online Learning Center


A decimal is a kind of fraction. It expresses a part of a whole.

The decimal point separates whole numbers from decimal places.

All decimal place names end in -ths.

To read a whole number and decimal, follow these steps:

Say the whole number first.

Say the word and for the decimal point.

Read the decimal as though it were a whole number.

Give the decimal a name according to the number of places it holds (tenths, hundredths, thousandths, and so on).

QUIZ: The digit 6 in the number 0.936 is equal to which of the following?

A) six tenths
B) six hundredths
C) six thousandths
D) six ten-thousandths
E) six hundred-thousandths

To write a decimal, follow these steps:

Think about the number of decimal places you need.

Use zeros to hold places where necessary.

Remember the word and separates whole numbers from decimal fractions.

Rounding is a useful tool for estimating answers to decimal problems.

QUIZ: Write three thousand forty-eight ten-thousandths in decimal form.

A) 0.03048
B) 0.3048
C) 0.348
D) 3000.48
E) 0.0348


To round a decimal, follow these steps:

Underline the digit in the place to which you are rounding.

 If the digit to the right of the underlined digit is greater than or equal to 5, add 1 to the underlined digit.

If the digit to the right of the underlined digit is less than 5, leave the underlined digit as it is. Drop the digits to the right of the underlined digit.

Adding and Subtracting Decimals 

To add decimals, follow these steps:

1.  Line up the decimals, with decimal point under decimal point.
2. Add each column.
3. Place the decimal point in the answer directly below the decimal points
4. above.

To subtract decimals, follow these steps:

1. Line up the decimals, with decimal point under decimal point. 
2. Subtract. 
3. Place the decimal point in the answer directly below the decimal points

Quiz: From a board that was 2 meters long, Matt cut a piece that was 1.65 meters long. Assuming no waste, how long was the remaining piece?

A) 3.65 m

B) 2.35 m

C) 1.35 m

D) 0.65 m

E) 0.35 m

Multiplying and Dividing Decimals

To multiply decimals, follow these steps:

1. Put the number with more digits on top and the other below.
2. Multiply as you would multiply whole numbers.
3. Count the number of decimal places in both of the numbers you multiplied.
4. Put the total number of decimal places in the answer.

QUIZ: Find the product of 5.09 and 1.4 rounded to the nearest tenth.

A) 7.126

B) 7.13

C) 7.1

D) 7

E) 10

To divide decimals, follow these steps:

1. Make the divisor a whole number by moving the decimal point to the right.
2. Move the decimal point in the dividend the same number of places.
3. Divide as you would with whole numbers.
4. Place the decimal point in the answer directly above its new position in the dividend.

*2002 McGraw-Hill Higher Education
Any use is subject to the Terms of Use and Privacy Policy.

McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.

Fraction Skills Review

Applying Addition Skills

Adding mixed numbers

Adding unlike fractions

Math Antics - Fractions and Decimals

How to Divide fractions by fractions

How to Divide fractions by fractionsDivide-Fractions-by-Fractions

Math Antics - Simplifying Fractions

Quiz 4

Click here to access to the quiz

What is a Decimal?

Maths the Wacky Way - Fractions

Three Simple Finance Questions

Source: Business Inside

1.  Suppose you had $100 in a savings account and the interest rate was 2 percent per year. After five years, how much do you think you would have in the account if you left the money to grow?

A) more than $102;

B) exactly $102;

C) less than $102;

D) do not know

2.  Imagine that the interest rate on your savings account is 1 percent per year and inflation is 2 percent per year. After one year, would you be able to buy

A) more than,

 B) exactly the same as

C) less than today with the money in this account?

 D) do not know

3.  Do you think that the following statement is true or false? “Buying a single company stock usually provides a safer return than a stock mutual fund.”

A) true

B) false

C) do not know; refuse to answer.

Quiz 3

Click here to access Quiz 3

Answers to Quiz 2

What parking spot # is the car parked in?

PEMDAS order

Click Here to access to PEMDAS order

Arthur Benjamin: A performance of "Mathemagic"

The square roots of some Natural numbers.

1 * 1 = 1

2 * 2 = 4

3 * 3 = 9

4 * 4 = 16

5 * 5 = 25

6 * 6 = 36

7 * 7 = 49

8 * 8 = 64

9 * 9 = 81

10 * 10 = 100

11 * 11 = 121

12 * 12 = 144

13 * 13 = 169

14 * 14 = 196

15 * 15 = 225

16 * 16 = 256

17 * 17 = 289

18 * 18 = 324

19 * 19 = 361

20 * 20 = 400

21 * 21 = 441

22 * 22 = 484

23 * 23 = 529

24 * 24 = 576

25 * 25 = 625

26 * 26 = 676

27 * 27 = 729

28 * 28 = 784

29 * 29 = 841

30 * 30 = 900

31 * 31 = 961

32 * 32 = 1024

33 * 33 = 1089

34 * 34 = 1156

35 * 35 = 1225

36 * 36 = 1296

37 * 37 = 1369

38 * 38 = 1444

39 * 39 = 1521

40 * 40 = 1600

Quick Math Review to Prep for Algebra 1

Quiz 2

Quiz 2

Rounding Whole Number Review

Quiz 1

1. If Lynn can type a page in p minutes, what piece of the page can she do in 5 minutes?


A. 5/p (Correct Answer)
B. p - 5
C. p + 5
D. p/5
E. 1- p + 5

2. If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

A. 2 hours and 24 minutes (Correct Answer)
B. 3 hours and 12 minutes
C. 3 hours and 44 minutes
D. 4 hours and 10 minutes
E. 4 hours and 33 minutes

3. Employees of a discount appliance store receive an additional 20% off of the lowest price on an item. If an employee purchases a dishwasher during a 15% off sale, how much will he pay if the dishwasher originally cost $450?

A. $280.90
B. $287
C. $292.50
D. $306 (Correct Answer)
E. $333.89

Lesson 1 - Whole Number Review

 Lesson 1 - Whole Number Review

Welcome to GED Math blog.

In this blog you will find more information to help you to improve your preparation for the Math GED test.

I plan to keep this blog update with Quizzes, Links, Videos and some other resources.

You can have access to this blog using any of your Internet devices (Tablets, Smart Phones, Computers, etc).

Hope you will find this blog useful.

Prof. Luis Bello

GED website

I recommend you to visit the GED website to learn more about the tests.

Here is the link: https://ged.com/