Unit 3.4: Multiplying decimals
So... we've made it this far. What do you think? Not too bad, right?
After learning how to add and subtract decimals, we arrive to the next important arithmetic function:
MULTIPLICATION!
And just like the addition and subtraction of decimals is very similar to the addition and subtraction of integers, the multiplication of decimals is very similar to the multiplication of integers. To give you a head start, I'd like for you to consider the following:
Now, take a look at the class' notes:
After learning how to add and subtract decimals, we arrive to the next important arithmetic function:
MULTIPLICATION!
And just like the addition and subtraction of decimals is very similar to the addition and subtraction of integers, the multiplication of decimals is very similar to the multiplication of integers. To give you a head start, I'd like for you to consider the following:
- Just like with integers, we multiply decimals from right to left, moving one space over every time a new digit begins to multiply.
- The best way to think of it is this: Proceed as you would proceed with integer multiplication; IGNORE the decimal points (that is, THE DECIMAL POINTS DO NOT HAVE TO BE LINED UP!), but count the TOTAL AMOUNT OF DECIMAL DIGITS IN ALL THE DECIMAL NUMBERS THAT ARE MULTIPLYING.
- At the end, after you have gotten your answer and using the total amount of decimal digits you previously counted, count from right to left, and place the decimal point immediately following the digit that falls on the counted amount of decimal digits.
- Because the area (what's inside) of all rectangles is equal to the product (multiplication) of their base and their height, rectangles are often used to model multiplication. In the notes, I explain how to use algebra tiles or base ten blocks to multiply decimals (as explained by the rectangle model). I am also including videos which do a great job of explaining this, so please make sure you
Now, take a look at the class' notes:
7e_unit_3.4.pdf | |
File Size: | 7910 kb |
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VIDEOS: for you, my visual learners!
Just as it is for all the unit pages on this website, video watching is not mandatory (unless I specify otherwise). But, they are a great way to ensure you get a very good grasp on all the concepts presented to you. Why not watch then?
So, if I may, I suggest you watch (even if just one). Ready?
This first video is the one we used on the previous sub-unit. Here, what is relevant to us starts at 3:40 min. Please make sure you start the video at 3:40, and stop it at 7:50 min.
So, if I may, I suggest you watch (even if just one). Ready?
This first video is the one we used on the previous sub-unit. Here, what is relevant to us starts at 3:40 min. Please make sure you start the video at 3:40, and stop it at 7:50 min.
Take a look at the following videos. They explain how to model multiplication using a rectangle ALGEBRA TILES, and BASE TEN BLOCKS:
practice worksheets
As always, I recommend you try doing the worksheets and coming up with your own answers. Then, feel free to check your answers by comparing them with the answers included in here. Good luck!
7e_unit_3.4_worksheets.pdf | |
File Size: | 2722 kb |
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Now, compare your answers with these answers:
7e_unit_3.4_worksheets_answers.pdf | |
File Size: | 2749 kb |
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online challenge practice activities
Because everybody can use a challenge to help them learn... Specially when it comes to word problems! Good luck.
extra practice
Why not try? Practice, practice, practice..... In your TEXTBOOK:
- Page 102: #1, #2, #3, #5, #8
- Page 103: #10, #12 and #13