See also the
Dr. Math FAQ:
3D and higher
Browse Elementary Fractions &
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Adding and subtracting fractions.
Finding a least common denominator (LCD).
Comparing/ordering fractions; equivalent fractions.
Improper fractions and mixed numbers.
Converting fractions to/from decimals.
Rounding fractions and decimals.
Fractions and repeating decimals.
- Fractions of Musical Notes [10/14/1997]
How many notes are in two sixteenth notes plus eighth notes with five
- Help With Multiplication and Percents [11/11/1996]
Can you help me with multiplication so that I can better understand
- Improper Fractions [04/15/1999]
I need help making improper fractions into mixed numbers.
- Inches, Feet, Yards, Miles, and Unit Fractions [01/29/2002]
I need to know if you multiply or divide in changing feet to inches, feet
to yards, miles to yards, feet to miles, yards to miles, yards to feet.
- Making Fractions into Percentages [04/30/2003]
What percentage is 3/5?
- Multiplication of Decimals [01/02/2002]
When numbers after decimal points are added together the decimal place
can then be placed that number of places from the right. Why? How does
- Multiplying and Dividing Decimals [6/27/1996]
Would you please explain multiplication and division of decimals?
- Multiplying and Dividing Fractions [01/23/2001]
We are trying to figure out how to understand division and multiplication
- Multiplying Fractions [04/11/1999]
The basics, with a step-by-step example.
- Multiplying Fractions [02/06/2001]
I need help solving 8/9 * 3/5. What is cross-cancelling?
- Multiplying Fractions and Mixed Numbers [03/12/1997]
How do you multiply fractions and mixed numbers like 1 1/3 x 1/4 =
- Multiplying Mixed Numbers [06/02/2003]
Can you multiply mixed numbers without changing them into improper
- Multiplying Mixed Numbers [05/28/1998]
Explaining and illustrating how to multiply fractions and mixed
- Reciprocals [12/19/1996]
What is the use of reciprocals?
- Reducing Fractions [3/7/1996]
How do you bring a fraction like 5/8 to its lowest term? Please explain
- Reducing Fractions [02/25/1997]
How do you reduce fractions?
- Reducing Fractions with Large Numbers [01/30/1998]
Is there a "trick" for going through the possibilities before declaring
that 4,5,6,7,8,9, digit number fractions may or may not be reduced?
- Relating Decimal Answers to Remainders [02/15/2002]
How did you divide 457/5 and get the answer 91.4, and why is it a
- Renaming Fractions [05/22/2000]
Can you explain renaming fractions in a way I can understand?
- Rounding Decimals [06/14/1999]
Is 1.9949 rounded to 2 decimal places 2.00 or 1.99?
- Simplifying Expressions with Fractions [9/2/1996]
How do I simplify 9(-1/7)(1/3)(-28) ?
- Simplifying Fractions [12/08/2002]
Finding and eliminating (cancelling) prime factors.
- Subtracting Decimals with Borrowing [10/09/2001]
How do you subtract 488.354 from 536.30?
- Turning a Repeating Decimal into a Fraction [10/18/2002]
How do I make a decimal like .063490634906... into a fraction?
- Understanding Common Denominators [07/16/1997]
What is a common denominator?
- Unit Conversions: mph to fps [03/06/2003]
How can I find out how many feet per second I could travel driving 55
miles per hour?
- Using Fractions to Read Decimals [08/29/2001]
Can you please tell me how to read in words, decimals such as: .02, .20,
- What is a Significant Digit? [12/25/2001]
I came across a question asking for an answer with no more than "2
significant digits" - can you please explain what a significant digit is?
- 3/4 of _____ Is 90 in Three Ways [03/24/2010]
In a multiplication problem like "Three-quarters of _____ is ninety," how do you fill-in-
the-blank with the factor that satisfies the equality? Doctor Ian presents three different
methods: guess-and-improve; the equivalency between multiplication and division;
and multiplying through by a reciprocal.
- 3 Methods for Finding Least Common Denominator [02/04/1998]
My fifth graders are having a very difficult time understanding how to
get the least common denominator. Any shortcuts?
- Adding a Zero When Multiplying a Decimal [06/21/2001]
I don't understand why you add a zero when multiplying decimals.
- Adding Fractions [6/5/1996]
Can you help me with this question? 1 1/2 + 4 3/2.
- Adding Fractions [7/26/1996]
How do you add fractions?
- Adding Fractions [11/10/1997]
How do you add 4 2/3 + 3 1/6?
- Adding Fractions [05/21/2002]
How do you add fractions?
- Adding Fractions [01/13/2003]
2/25 + 2/15 equals what?
- Adding Fractions Without Using the LCD [11/18/1999]
I think I've found a new way of adding fractions that doesn't require
finding the LCD. Can you tell me whether or not my method works, and if
it is a new discovery?
- Adding Mixed Numbers [12/10/1995]
3 1/4 + 5 3/12
- Adding Tax and Tip [07/19/1998]
In pricing our hotel luncheons, we charge a base price plus a 6.8% tax
and a 20% service charge. How would I find the total in one step?
- Bar over a Whole Number? [06/05/2001]
What does a bar over a whole number indicate?