See also the
Dr. Math FAQ:
3D and higher
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Flashcards/worksheets on the Web.
Order of operations.
- (9/2)/(3/4): A Picture [03/27/2003]
We were trying to find a division fraction question and everything we
came up with turned into a multiplication fraction problem. Why is
- Basic Real Number Properties [07/31/1997]
I need information about basic real number properties: associative,
commutative, closure, identity, inverse, distributive.
- Checking Division [08/18/1998]
I know how to divide pretty well, but I always get the check wrong.
- Dividing 800 by 500 [11/7/1994]
A nine-year-old asks: How can I divide 800 by 500?
- Dividing a Whole Number by a Fraction [04/02/1997]
How do you divide a whole number by a fraction?
- Dividing by a Fraction [06/29/1999]
Why is it that when you divide by a fraction, your answer is larger?
- Dividing by a Fraction [6/7/1995]
Why is it when dividing fractions you have to multiply by the reciprocal?
- Dividing Candy Among Friends [04/04/1997]
I have 48 pieces of candy that I want to give to 6 friends. How many
pieces of candy will each friend get?
- Dividing Decimals by Whole Numbers [10/19/2002]
Dividing decimals has been hard for me to learn.
- Dividing Fractions [09/08/99]
How do you divide fractions?
- Division [11/25/1997]
How do you divide 1,000,000,000,000 by 999,999,999,999,999,999,999?
- Division Problem [7/12/1995]
What is eighty divided by one hundred?
- Division Table [01/25/1999]
Can we use the multiplication table to learn division?
- Learning Long Division [2/2/1996]
We are about to study long division. I want to learn more about it before
the rest so I can be ready instead of waiting for the math book!
- Least Common Multiple Puzzle [03/24/2003]
What is the smallest number divisible by 1,2,3,4,5,6,8,9,10 that is
- Long Division [08/23/1998]
My biggest problem is long division. For example, what is 73/4?
- Long division [11/15/1994]
Could you help us with one of our third grade really hard math problems?
Here it is: 7626614 / 255 = ?
- Long Division [03/16/1999]
A step-by-step example of long division.
- Manipulating Positive and Negative Numbers [8/9/1996]
Could you explain the rules for adding, subtracting, multiplying, and
dividing positive and negative numbers?
- Multiples of 9 Number Puzzle [03/23/2003]
If you take a two-digit number, add the digits, and subtract the sum
from the original number, why is the answer always a multiple of 9?
- Order Of Operations in Four Steps [02/15/1998]
I need help figuring out what operation to do first.
- Order of Operations: Math vs. English; Calculators [11/13/1996]
What is 144 divided by 3(8+4)? 4 or 576?
- Putting Division into Words [04/06/1999]
How many times does 4 go into 600? Why?
- Reciprocals [12/19/1996]
What is the use of reciprocals?
- 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
- Remainders [01/30/2001]
What do you do with the remainder in division?
- Rule for dividing by 7 [12/1/1994]
Many years ago, I taught from a math text that gave "divisibility rules"
for the numbers one through ten. For example, "if the sum of the digits
of a number is divisible by three, the number is divisible by three." I
remember the rules for all the numbers except "7". I've looked in every
reference book I could think of, but have had no luck. Any chance you
could help me out here?
- Three- and Four-Digit Long Division [03/15/1999]
Could you explain how to do division problems such as 67932/918 and
- What is 1000 Divided by 7? [4/27/1995]
Our class is on division. What is 1000 divided by 7?
- What is 12/8 ? [4/27/1995]
Hi, we are studying division. What is 12/8?
- Wording Division Problems [08/10/1998]
How would you clarify the wording of division problems like "divide into"
or "divide by"?
- Working with Integers [01/12/1999]
Could you explain how to divide, multiply, add, and subtract integers?
- 1 Divided by Very Small Number [8/6/1996]
1/0.00000000000000000000000000000000001 = ?
- 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.
- Adding Zeros in a Long Division Problem [02/26/2006]
I am teaching my daughter long division and I want to make sure that I
understand the rules about adding zeros correctly.
- Are Subtraction and Division Commutative and Associative Operations? [05/15/2008]
I don't agree that subtraction and division are not commutative
operations. If we define a - b as a + (-b), then it commutes correctly
into (-b) + a. So why does everyone say subtraction is not commutative?
- Arranging Blocks in Groups [06/13/1998]
Elise wants to make a rectangular arrangement out of 24 squares. One side
must be 8 squares. What will be the dimensions of the rectangle?
- Basic Math [11/15/1994]
What is 9/10/30/999/1000000/99991000/4444444/4444444444444444444444/
88888/999999999= . . . Are you good at / ;-)
- Brackets [01/29/2001]
Please explain how brackets  work.
- Broken Eggs [12/12/1996]
When a farmer puts eggs in groups of 2, 3, 4, 5, and 6, there is always
one egg left over. With groups of 7, there are no eggs left over. How
many eggs are there?