SOLUTION: A multipling procedure for 28x32.

Question 7001: A multipling procedure for 28x32.
Answer by prince_abubu(198) (Show Source): You can put this solution on YOUR website!
I don't exactly know what you mean. Are you looking for another way to solve 28 * 32 besides how you were taught in elementary?

I know a trick you can use with this kind of problem. Say we have two numbers m and n that we are to multiply. It's easiest if their one's digits add up to 10, and their tens digits have a difference of 1.

There is a topic in polynomials that is brought out to students' attention (usually refered to as the difference of squares) - What happens when you perform FOIL on a product of the form (a + b)(a - b)? It becomes a^2 - b^2. We'll use that trick to solve this type of multiplication problem.

We can say that 32 = 30 + 2 and 28 = 30 - 2. So we have the product (30 + 2)(30 - 2). That's EXACTLY in the form (a + b)(a - b). If (a + b)(a - b) really equals a^2 - b^2, then we can say 30^2 - 2^2 which is 900 - 4, which finally equals 396.

Another example: 44 * 56. 44 = 50 - 6, and 56 = 50 + 6. (50 + 6)(50 - 6) = 50^2 - 6^2 = 2500 - 36 = 2464.

So how would two numbers qualify for this type of multiplication again?
RELATED QUESTIONS
what is the inverse operation for 0+2? Is... (answered by rfer)

Assume that a procedure (answered by richwmiller)

Assume that a... (answered by richwmiller)

give a procedure for determining the number of zeros at the end of n!.justify your... (answered by Edwin McCravy)

Well i need help on algebra for solving equations , multipling . please help me . (answered by unlockmath)

Is there a strategy which explains the step-by-step procedure for solving algebraic word... (answered by ewatrrr)

What are the steps to solving equations by multipling by a reciprical and by a common... (answered by apachemexican1)

If a particular medical procedure has a 95% success rate for each time it is performed.... (answered by ewatrrr)

Provide an appropriate response to the followings. (a)Under what conditions would you... (answered by stanbon)