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Elementary Archive

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

Selected answers to common questions:
    Flashcards/worksheets on the Web.
    Order of operations.
    Number sentences.
    What is 1+1?

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Number Puzzle with Digits 1-9 in a 3 by 3 Grid [10/09/2006]

In a 3 cell by 3 cell grid, use the digits 1 through 9 to fill in the cells so each horizontal, vertical, and diagonal row of three has a sum of 15. I've tried many possibilities with no luck!

One Plus One [04/11/1997]

Are you sure that 1 plus 1 equals 2?

Ordering the Operations [11/10/1998]

Why does the order of operations have to be in that order? Who set that specific order of operations?

Order of Operations [01/25/1998]

Evaluate the expression: 30 - 5^2 + 4^3.

Order of Operations and Fractions [02/22/2002]

Given a+3 and b+5, is 105 / ab 7 or 175?

Order of Operations: Parentheses as Packages [10/25/2001]

I need help figuring out the steps in this expression: 5-{-4[2^4-11(-9- 1)]}=

Order of Operations vs. Associative Property [10/10/2002]

Is the associative property an exception to the order of operations, a corollary, or something totally unrelated?

Order of Operations vs. Distributive Property [02/04/2005]

Does the distributive property contradict the rules of order of operations? When we have a(b + c) order of operations says we should add first in the parentheses, then multiply, but the distributive property says we can multiply first to get ab + ac, then add.

Parts of a Subtraction Problem [04/09/2001]

What are the numbers 4 and 1 called in the subtraction 4 - 1 = 3?

Price of Pencils [10/07/2002]

Each year for the last 7 years the price of pencils has increased, and the new price is the sum of the prices for the two previous years. Last year a pencil cost 60 cents. How much does a pencil cost today? How much did a pencil cost 7 years ago?

Proof that 1 + 1 = 1? [09/04/1997]

Can you shed any light on this subject?

Properties [10/15/1997]

My daughter's homework asks: Which property is being shown? Commutative, Associative, Identity...

Properties, Defined and Illustrated [10/10/2001]

I need a page of information on the commutative, associative, and F.O.I.L. properties.

Sum of Products [11/01/1999]

When a word problem refers to the sum of the products, what exactly does it mean?

Teaching the Concept/Meaning of Sum [10/23/2001]

To me "the answer to an addition problem or equation" is not a true or necessarily useful definition. I define the sum as the whole or total...

Teaching your Baby Math [7/6/1996]

I saw a TV program about a baby college that taught babies how to read dots which they would add or subtract.

Using Addition and Subtraction to Check Answers [02/25/2003]

How can you use addition to check subtraction? How can you use subtraction to check addition?

Using Properties to Make Addition Easier [10/15/2003]

My daughter is being asked to use the commutative, associative, and identity properties of addition to help her add mentally. We're not sure what she's supposed to do.

Using the Distributive Property [08/23/2001]

My math teacher told us to work problems like this: a(b-c)= ab-ac.

Value of 7 [04/29/2002]

How do you find the value of 7?

Ways to Add and Divide More Easily [11/17/2008]

I have to add 2398 and 5752 and then divide by 37. I can do it, but it takes a long time. Is there any faster way to do those calculations?

What is 1 plus 1? [7/2/1996]

What is 1 plus 1?

Why Casting Out Nines Works [10/13/2008]

Can you explain in simple terms why the Casting Out Nines method works?

Why Is Mental Math Important? [03/25/2004]

How can I convince a 14 year old girl who is in 8th grade the importance of mental math? I think that skills like mentally adding and subtracting 2 digit numbers and being able to estimate multiplying 2 digit large numbers are critical. My daughter's teacher says that such skills aren't needed because of calculators and computers.

Why Rules? [08/15/2001]

Why do we need to have rules for order of operations?

Why Two Odds Always Sum to an Even [03/21/2002]

Why do two odd numbers always equal an even number but two even numbers never equal an odd number?

Working in Base 7 [08/02/2007]

How do I add, subtract, multiply and divide in base 7?

Working Up to Counting Up [09/25/2003]

My daughter wants to learn how to make change by counting up.

Years B.C. + A.D. [10/01/1997]

What's the difference in the ages of two people if one was born in 27 B.C.and the other was born in 16 A.D.?

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