1. Multiple Multiple Digit Whole Numbers
Subtitle

2. Estimate to Eliminate
Take each number and round it to the HIGHEST place value
179 rounds to the nearest hundreds
28 rounds to the nearest tens---30
200 x 30 = 6000
Our answer should be close to 6000….
answer should be lower than 6000, but not to much lower. (100 x 30=3000)

3. Algorithm-set of instructions that leads to a predictable result
Standard Algorithm
Algorithm-set of instructions that leads to a predictable result
This is the “way” we learned
This is the most efficient way to multiply multiple digits by multiple digits.
Multiply 8 by 9=72-record the 0 and “carry” the seven (above the tens place)
Multiple 8 by 7=56 + 7=63-record the 3 and “carry” the 6 (above the hundreds place)
Multiple 8 by 1=8 + 6= 14
Add your “sneaky” zero
Multiply the 2 by 9=18-record the 8 and “carry” the 1 (above the tens place)
Multiply 2 by 7=14 +1=15-record the 5 and “carry” the 1 (above the hundreds place)
Multiply 2 by 1=2 +1=3
Add =5012

4. Partial Product
Remember: numbers are made up of digits and those digits have value. (Digit x Place Value=Value). Multiply each place value by the bottom numbers place value.

5. Area Box (Rectangle Method)
Expand each of the numbers by their place value. 179=( ) and 28 (20+8)
Area is Length x width….well each box gets a value when you multiple the length by the width. For example, 20 x 100 = 2000
Add all the boxes (partial products) together to get the product