Two-Digit Multiplication Mathmagic
M48ortal on 02/04/2009
|READ THIS CAREFULLY - Here's a shortcut that you can use to amaze your friends and family, and maybe even your teacher. You can multiply 2 two-digit numbers quickly if they meet two simple conditions: 1.) The ones places add up to 10, and 2.) the tens places are equal. For our example, we will use 68 X 62. These numbers are between 60 and 70 (in red on our diagram). Step 1: Multiply the tens digit (6) times the next higher number (7). This gives you the thousands and hundreds places of your answer (42). Step 2: Multiply the ones places (8 X 2). This gives you the tens and ones places of your answer (16). So 68 X 62 = 4216. Another quick one? OK, 29 X 21: I get 2 X 3 = 06 and 9 X 1 = 09, so my answer is 609. We can drop the 0 from in front of 6, but have to keep the 0 in front of 9, since it will be a placeholder. Got it? Now practice on these ten problems so you can be a Mathmagician!|
Drop me a comment if you want an algebra explanation.
|Player:||Level:||% Correct:||Time to Complete:|