See also the
Dr. Math FAQ:
order of operations
learning to multiply
3D and higher
Browse Elementary Multiplication
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Flashcards/worksheets on the Web.
Learning to multiply.
Least common multiple, Greatest common factor.
Order of operations.
- How Many Border Stamps? [04/17/2001]
How many stamps are on the border of a 10x10 sheet of 100 stamps?
- How to Learn the Multiplication Table [09/01/2005]
Dr. Achilles, who struggled with the multiplication table as a kid,
relates some handy rules to help any student learn the table without
relying on rote memorization. It's a long article, but potentially
helpful to people struggling to learn or remember their multiplication
- Identity Element [10/12/2001]
What is an "identity element"?
- 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?
- 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 Arithmetic Problem [6/2/1995]
What is 784756895786 * 37846738654765485 + 547847358743 ?
- Lattice Method of Subtraction? [06/13/2006]
I've learned about the lattice method of addition and multiplication.
Is there a lattice method of subtraction?
- Learning Addition and Multiplication with Algebra [3/16/1996]
How do you know what the (a) is in algebra? I saw this on a picture:
a(1/a) = 1/a(a) = 1...
- Learning the Times Tables [10/12/2008]
I have a hard time with the times tables, and so I don't enjoy math.
Is there an easy way to get better at them?
- Learning Times Tables [12/06/2005]
I'm having trouble learning my times tables. Can you give me any help?
- Learning to Multiply and Divide Quickly [9/28/1995]
Do you have any ideas how I can learn to multiply and divide faster?
- Learning to Multiply Three-Digit Numbers [07/03/1998]
I would like to learn how to do multiplication of bigger numbers, like
120 x 743.
- Least Common Multiple [09/29/2001]
What is the least common multiple of 11, 13, and 17?
- Least Common Multiple with Zero [03/26/2003]
I'm trying to find any reference about the least common multiple of
two numbers when one (or both) is zero.
- Lengths in Pictures [4/5/1996]
A picture of an insect is k times the actual size. If the leg on the
picture is 3cm long, how long is the leg on the actual insect?
- Lining Up Decimal Points [03/03/2003]
Why do we line up decimal points for addition and subtraction but not
for division and multiplication?
- Macintosh Elementary Math Software [01/14/1997]
Internet resources and information for multiplication/computation.
- Massive Multiplication! [11/2/1994]
A first-grader wants to know if Dr. Math is good at multiplication.
- Meaning of Multiplying Fractions [12/09/1999]
What does it mean to multiply a fraction by a fraction?
- The Meaning of Powers, such as Squares and Cubes [3/14/1996]
What does the power mean? Like 5 to the power of 2?
- Memorizing Multiplication Tables [2/26/1996]
I'm a 3rd grade teacher and my lesson is on 6x7, 6x8, and 7x8 in
multiplication. I only know a trick for memorizing 7x8. Do you have any
suggestions for 6x7, 6x8 and others?
- Mental Math [07/25/2003]
I would like to find a trick for multiplying by 3367.
- Multiples [11/08/2001]
What is the most common multiple of 13 and 7? I have no clue what they
are even talking about.
- Multiples of Four [03/01/1999]
Is zero a multiple of four?
- Multiplicand, Multiplier [07/05/2001]
Do you agree with me that in the following mathematical sentence: 456x10,
456 is called the multiplicand and 10 is called the multiplier?
- Multiplication [02/11/1999]
How many decimal places should the product of 3.26 and 0.25 contain?
- Multiplication Before Addition [5/31/1996]
1000 * 20000 + 34 - 4023 = ?
- Multiplication Facts [02/12/2002]
Can you use the same multiplication fact to find 4x50 and 5x40? What is a
- Multiplication Makes It ... Smaller?! [07/21/2012]
The counterintuitively small products of some multiplication problems really bug a
student. By writing out and sketching a pattern, Doctor Peterson re-presents
multiplication — as scaling, and as an operation undone by division.
- Multiplication of Fractions [03/22/1999]
What are cancellations?
- Multiplication Signs [10/07/2002]
Why are there different ways to indicate multiplication?
- Multiplication Tables on the Web [11/24/1996]
Can you tell me where I can find the multiplication tables on the WWW?
- Multiplication Trick [02/08/1998]
When I multiply 25x25 I can do the answer in my head by multiplying the
first digit times the next highest number and then writing 25. Why does
- 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"?
- Multiply: 16 x 200 [12/6/1994]
I want to know the answer to the problem sixteen times two hundred.
- Multiplying 3+9 [11/15/1994]
A well-nested problem.
- Multiplying a 3-digit Number by a 2-digit Number [10/10/1995]
What is 697x56?
- 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 a Number by Zero [09/14/2001]
When any number is multiplied by zero, why is the result zero?
- Multiplying Billions [12/17/1997]
How do you multiply 50 billion by 55 septillion?