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Partial Products Multiplication. How to multiply multi-digit numbers. What is a partial product?.
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Partial Products Multiplication How to multiply multi-digit numbers
What is a partial product? • Partial means part of and when we use this method, we are breaking the numbers or factors into smaller parts--I am calling them chunks because you are familiar with that term from reading! But we are working with a smaller part first before we put the factors all together to find the product. Can you see the word part in partial?
What do I do first? • When multiplying with multi-digits, the first thing we want to do is use expanded notation to break down the numbers or factors into smaller chunks. This helps us do one piece at a time. • For example, let’s break down the top number in this number sentence: • 543 can be expanded to 500 + 40 + 3 • x 3
Step 2 • You will want to set up the problem vertically and make sure to include the bottom number with each chunk of the expanded number. • For example, 543 x 3 should look like this: • 500 + 40 + 3 • X 3 x3 x 3
Step 3 • Do the work of multiplying each chunk. You can work from the left to the right or the right to the left. • 500 + 40 + 3 X 3x3x3 1500 120 9
Step 4 • Now you will add all the chunks or partial products together. Make sure you are aligning the numbers with the correct place value spacing: • 1500 • 120 • + 9 1629
Step 5 • Check your work! • 1. Did you add all the parts? Did you add them all correctly? • 2. Are your place values aligned correctly? • These two points are very important and usually where any mistakes are made.
Step 6 • Did you know you can ALSO check your work by using the traditional method of multiplying? • ‘543 • X 3 • 1629
Let’s try this again • Remember, we want to use expanded notation first. • 658 will look like this 600 + 50 + 8 • x5 • Now we want to set up the problem like this: • 600 + 50 + 8 • X 5 x5x5 Now do the multiplying! • 3000 + 250 + 40 = 3290
How did you do? • Are you ready to try it on your own? • Of course, you can work with a table buddy if you’d prefer…