Ask Dr. Math
Dr. Math Home ||
Middle School ||
High School ||
Dr. Math FAQ
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.
- Fraction vs. Decimal [08/29/1997]
What is the difference between 1/2 and 0.50?
- Greatest Common Factor (GCF) [04/13/1999]
How do you find the greatest common factor?
- Hidden Decimal Points [02/04/2002]
I get confused when subtracting 4 from 24.98. I keep coming up with
24.94. Could you explain why whole numbers do not show their decimal
- How Can Division Result in an Increase? [10/29/2003]
How is it possible for division to give you a larger number, instead
of a smaller one?
- How Many Days in the Month? [01/22/2004]
There were eleven days of rain one month in Boston. Of the remaining
days, two-fifths were sunny, one-fourth were cloudy, and it snowed the
other seven days. How many days were in the month?
- How Many Significant Digits? [10/17/2001]
Why does 5030 have three significant digits and 5030. four?
- How Much of a Total Price Is the Tax? [10/20/2003]
If an item has been purchased and all you know is the total cost for
the item and tax, how can you determine how much tax was charged?
- How to Divide Decimals by Decimals [03/07/1998]
I don't understand dividing decimals ...
- How to Pronounce a Fraction of a Percentage [07/07/2005]
Is it correct to say "one tenth of one percent" as opposed to saying "one tenth percent" for 0.1%? Why or why not?
- Ignoring Zeros [09/03/1998]
Are 0.76 and 0.760 equal? When can you ignore the zeros?
- Improper Fractions [05/20/2002]
How can 14/9 be a fraction when you can't have 14 parts of something
that's been cut into 9 parts?
- Improper Fractions and Mixed Numbers [09/10/1997]
What do you do when the numerator of a fraction is bigger than the
- Inches and Feet in Decimal Form [7/16/1996]
How do I convert fractions of inches and feet into a decimal expression
of the length in feet?
- Introduction to Division with Negative Numbers [05/05/2004]
I don't know how to do division with negative numbers, like +18/-9
or -24/-8 or +21/-3.
- Invert and Multiply [11/08/1997]
I am struggling with how to explain to a class WHY we invert and multiply
when dividing fractions.
- Is Division Sharing? [09/08/2001]
Why in fraction division is the answer larger than the first fraction?
- The Joy of Fractions [05/18/2002]
How come fractions are called fractions? How come they can be
translated into decimals? Why do they hurt your brain when you
first learn them?
- Learning Decimals [10/19/1998]
Can you explain decimals to me?
- Learning Fractions in the Metric System [11/27/2003]
Since the metric system doesn't use fractions, are math students in
metric countries able to skip fractions and work on more useful things?
- Longfellow's Bees [08/01/2002]
One-fifth of some bees fly to the rosebush, one-third fly to the
apple tree, and three times the difference fly to the acorn tree. One
bee is left flying around. How many bees are there altogether?
- Meaning of Multiplying Fractions [12/09/1999]
What does it mean to multiply a fraction by a fraction?
- Measures of Music and Fractions [01/13/1999]
How can you tell what fraction of a measure a note is? How does it relate
to the time signature?
- Mixed Numbers [03/20/2001]
I am having trouble with mixed numbers. Is there an easy way to remember
how to do them?
- Mixed Numerals [2/14/1996]
How can 7/3 be 2 and 1/3?
- Moving the Decimal Point [12/04/2002]
When you divide two decimals, what is it called when you move the
- Multiplication [02/11/1999]
How many decimal places should the product of 3.26 and 0.25 contain?
- Multiplication of Fractions [03/22/1999]
What are cancellations?
- Multiplying a Fraction by a Decimal [9/5/1996]
How do I simplify and multiply (40/360) by 78.5?
- Multiplying and Adding Fractions [04/01/1997]
How do I solve (1/3 + 2/5) * 3/4 ?
- Multiplying and Dividing Mixed Numbers [6/5/1996]
How do you divide 1 1/2 by 9/10 or multiply 8 1/4 by 2 2/3?
- Multiplying by 1000 [03/10/1997]
What is 2,542 times 1,000?
- Multiplying by a Decimal [11/10/1994]
How come when you multiply 0.36 and 88 you get 9.4270, which is less than
what it should be?
- Multiplying by a Decimal Number [02/28/2001]
I am having trouble understanding why multiplying by decimal numbers
gives a product smaller than the factors.
- Multiplying by Fractions and Decimals [5/31/1996]
What number is 3/10 more than .025?
- Multiplying by the Reciprocal to Divide Two Fractions [05/08/2008]
Why does it work to divide two fractions by multiplying the numerator
times the reciprocal of the denominator?
- Multiplying Decimal Numbers and Placing the Decimal Point [09/20/2007]
Why does counting up the total decimal places when multiplying decimal
- Multiplying Decimals and Decreasing Answers [12/02/1998]
Why does multiplying by a decimal decrease the answer? How can you have
less than what you started with when you multiply?
- Multiplying Decimals by Negatives [03/18/2002]
I can't find decimals on my calculator.
- Multiplying Fractions [1/28/1996]
I need help with problems such as this one: 3 1/4 x 3/4 = ?
- Multiplying Fractions [01/20/1997]
If multiplication is defined as repeated addition, why is the product of
two fractions smaller than either of the fractions?
Search the Dr. Math Library:
© 1994-2013 Drexel University. All rights reserved.
Home || The Math Library || Quick Reference || Search || Help
The Math Forum is a research and educational enterprise of the Drexel University School of Education.