Introduction[]
Long multiplication, sometimes called grade-school multiplication or the Standard Algorithm, is an algorithm for multiplying large numbers that's factors are greater than 9.There's strategies you can use to be able to multiply long multiplication.
Methods[]
Method 1:The window/area method[]
Information[]
You basically make a chart,the left/right are one factor and the top/bottom is another,so basically the boxes are multiplied based on which row and column they are.For each side,the factor has to be split based on Place Value.After you are done,add the partial products to get your product.Let me show you a example.
Example[]
19*28=(10*20)+(10*8)+(9*20)+(9*8)
| 200 | 180 |
| 80 | 72 |
200+80+180+72=532
Method 2:The Standard Algorithm/Mental Math[]
If you don't need to use a model to be able to do Long Multiplication,you can do the equation yourself using Mental Math.
19*28=(10*20)+(10*8)+(9*20)+(9*8)
=532
Quiz[]
Quiz Questions[]
- 1. What is 45*18? (Use mental math to solve)
- 2. What is 23*14 (Use any strategy you like)
A) 322
B) 200
C) 312
D) 422
- 3. Which Window Model is correct for doing 72*25? (Use Window/Area Model)
A)
| 140 | 40 |
| 35 | 10 |
B)
| 1400 | 4000 |
| 3500 | 1000 |
C)
| 1400 | 40 |
| 350 | 10 |
Quiz Answers[]
1) 810
2) 322
3) C