Multiplying 4's from Mathmagical on Vimeo.
The idea behind Multiplying Time! is quite simple; help students learn multiplication strategies that can help them solve problems far beyond the typical “12 x 12″ operation. By learning and memorizing strategies, a student will possess a tool that is far greater than the standard multiplication algorithm. Here are some examples:
Track numbers 2, 3, and 4 from Multiplying Time! teach doubling strategies. Track number 2 addresses multiplying by 2. When multiplying anything by 2, the answer is as simple as doubling. As an example, 8 doubled, or 8 + 8, equals 16. The same strategy enables a student to solve 37 x 2, or 37 + 37, which equals 74. (This of course presumes that the student is proficient at addition). Track number 3 addresses multiplication by 4. When multiplying by 4, the answer is as simple as the double-double strategy. As an example, 8 x 4, is just like saying, 8 + 8 = 16 (double), then 16 doubled, or 16 + 16 = 32. Take that a step further for multiplying by 8 using a double-double-double strategy. Staying with the number 8, you’d say 8 doubled, or 8 + 8 = 16, then 16 doubled, or 16 + 16 = 32, then 32 doubled, or 32 + 32 = 64.
Hopefully this gives you an idea of how utilizing a strategy is better than memorizing an algorithm. Using the double-double-double strategy, what is 37 x 8?