Multiplication is a wonderful way to explore mathematics as well as develop mental powers of agility, memory, flexibility and creativity.
Here are seven methods covered in the course:
- Base method e.g. 87×97, Lesson 14,15 (and 31×33 using Proportionately)
2. Average e.g. 41×39, Lesson 17 (and 82×39 using Proportionately)
3. By One More e.g. 74×76, Lesson 17 (and 47×86 using Proportionately)
4. Doubling & Halving e.g. 35×46, Lesson 7
5. Eleven e.g. 43×11 (and 52×22 using Proportionately), Lesson 12
6. Addition & subtraction e.g. 34×19, Lesson 2
7. General method (vertically and crosswise) e.g. 23×31, Lesson 13
(Lesson 32 shows another multiplication method)
You can use addition and subtraction with the other methods too. For example, for 23×42 you could think of this as 22×42 + 42, so that you can use the 11 method to find 22×42 and add 42 to it.
Try these:
62 x 58 = 42 x 43 = 11 x 56 =
65 x 85 = 41 x 38 = 38 x 39 =
71 x 79 = 72 x 45 = 87 x 11 =
31 x 21 = 78 x 36 = 21 x 53 =
Can you give a pair of numbers whose product cannot be found by any of the first 6 methods above?
Can you find a pair of numbers whose product can be found using all of the methods above?