Ask Dr. Math

Elementary Archive

Browse Elementary Division
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    Dividing fractions.
    Flashcards/worksheets on the Web.
    Long division.
    Order of operations.
    Number sentences.

---

Error: Division by Zero [02/12/2001]

How can I explain to my third grader that a number divided by zero is undefined? The school calculator gives the answer 0/E, and the Windows calculator gives positive infinity.

Estimating and Rounding [03/04/2002]

Divide a two-digit number into another number and get a one-digit quotient.

Etymology of the Word 'Quotient' [11/25/2002]

What is the origin of the word 'quotient'?

Evaluating Parentheses, Brackets, Braces and Grouping Symbols [01/20/2007]

How do I evaluate or simplify an expression with lots of grouping symbols, like (18/2){[(9 x 9 - 1)/ 2] - [5 x 20 - (7 x 9 - 2)]}?

Explaining Order of Operations [09/06/2001]

How would you explain the order of operations to a 5th or 6th grader who has not yet studied the subject?

Factoring and Cancelling in Long Division [08/29/2003]

How do I perform long division? i.e. 1,002,240,000 / 86400

Find a Four-Digit Number Divisible by 2, 3, and 9 [11/29/2003]

How to determine a possible answer by applying the standard divisibility rules for 2 and 9.

Five from Twenty-five [07/22/1997]

How many times can you take 5 away from 25?

The Forgiving Method of Division [05/14/2002]

Can you explain the 'forgiving' method of division?

Formula for Greatest Common Divisor [01/08/1997]

Is there a formula to get the greatest common factor?

A Four-year-old Thinks About Even and Odd Numbers [07/22/1999]

"Half" means 2 parts, and some numbers are not that way. Mom says they're "odd." It's not fair letting 2 be even all by itself!

Fraction Division Diagrams [04/21/1999]

Diagram 1 divided by 1 1/2.

Fractions and Adding Zeros [08/26/2001]

I am having problems with doing fractions on the calculator.

Fundamental Idea of Division [03/24/2000]

My 8-year-old daughter had 12 bracelets which she arranged into 4 piles of 3. Did she divide 12 by 3 or by 4?

Galley or Scratch Method of Division [12/08/2002]

In the 15th century, what was the method for performing division?

Greatest Common Factors, Least Common Multiples [8/29/1996]

Please explain greatest common factors, how to find them, and how they are different from lowest common multiples.

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 to Divide Decimals by Decimals [03/07/1998]

I don't understand dividing decimals ...

Importance of Considering Units in Division Problems [01/27/2005]

"Draw a picture to show the problem then write a division sentence. Bobby has 12 model cars. He puts them in cases. Each case holds 4 cars. How many cases does he fill?" My son drew 3 boxes with four dotsin each and wrote 12/3 equals 4 and answered that bobby filled 3 cases. Shouldn't it be the other way around?

Incorrect Application of PEMDAS and Order of Operations [09/14/2006]

My students think PEMDAS means that all addition should be done before any subtraction is done. How can I show and convince them that they need to do both operations at the same time working from left to right?

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.

Is Division Sharing? [09/08/2001]

Why in fraction division is the answer larger than the first fraction?

Is the 2 Related to the Numbers in Parentheses? [10/05/2001]

Order of operations: Which is the correct way to solve this problem: 36/2(8-5) = ? What's a comparable English sentence?

Large number division [11/16/1994]

Do you know what 1,223,444,777,888,999 divided by 1,999,888,777,666,555,444,333,222,123 is? How is it to be a math whiz?

Least Common Multiple [09/29/2001]

What is the least common multiple of 11, 13, and 17?

Lining Up Decimal Points [03/03/2003]

Why do we line up decimal points for addition and subtraction but not for division and multiplication?

Long Division [1/24/1996]

Could you please tell me how I can divide 5 by 7 - the answer and how you arrived at it?

Long division [6/16/1996]

How do you do 65423543/123654+1111-31235 ?

Long Division, Egyptian Division, Guessing [06/13/2001]

Is there another method for two-digit division that doesn't involve guessing?

Longer Division [09/27/2002]

My daughter does not understand how to divide.

Making Division Fun [10/26/1995]

How can division be less boring?

Making Guesses, Correcting Mistakes [06/07/2001]

I couldn't "bring down" because 9 is higher than 6.

Making up a Division Word Problem [11/13/2001]

Write a problem that could be solved by using the division sentence 1489/28=n; then write a pair of compatible numbers and estimate the quotient.

Moving the Decimal Point [12/04/2002]

When you divide two decimals, what is it called when you move the decimal point?

Moving the Decimal Point to Divide [02/28/2009]

Why do we move the decimal point over when doing decimal division? For example, in the problem 100/0.4, why do we move the decimal and make it 1000/4?

Multiple Subtraction by Missing Addend Method [09/26/2002]

To get the difference by the missing addend method we are not supposed to change the given problem into subtraction of one subtrahend, but to work out the problem as it is. We are not even to use regrouping.

Multiplier, Sum, Difference, Product, Quotient, Dividend [11/25/1997]

What is a multiplier? an addend? a minuend? a product? Why is the number that is being divided the "dividend"?

Multiplying and Dividing Negatives [07/20/1998]

Can you explain multiplication and division with signed numbers? For example what is the sign when you multiply negative numbers?

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 Mixed Numbers [06/02/2003]

Can you multiply mixed numbers without changing them into improper fractions?

Page: [<prev]  1  2  3  4 [next>]