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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?\r
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\n" ); document.write( "\n" ); document.write( "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.
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\n" ); document.write( "\n" ); document.write( "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.\r
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\n" ); document.write( "\n" ); document.write( "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.\r
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\n" ); document.write( "\n" ); document.write( "Another example: 44 * 56. 44 = 50 - 6, and 56 = 50 + 6. (50 + 6)(50 - 6) = 50^2 - 6^2 = 2500 - 36 = 2464.\r
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\n" ); document.write( "\n" ); document.write( "So how would two numbers qualify for this type of multiplication again? \n" ); document.write( "