LI: How to multiply decimals using algorithims
This week in class, Group 1 are learning about multiplying decimal numbers. Multiplying decimals is very similar to multiplying regular whole numbers. The main difference is that after you do the multiplication, you need to figure out the correct place for the decimal point in the answer.
Here’s how it works:
First, you ignore the decimal points from the numbers you’re multiplying and just multiply the numbers as if they were whole numbers. When setting up the problem, you don’t need to line up the decimals perfectly; just focus on multiplying the digits as usual.
Next, when you start multiplying, you set everything up normally: line up the numbers to the right and multiply as if they were whole numbers. During the process, if you need to move to the next digit (like moving from ones to tens), you might add a placeholder zero to keep track of places and make sure the multiplication is accurate.
Finally, after you get the full product (the answer), you count how many decimal places there were in the original numbers you’re multiplying. For example, if one number had two decimal places and the other had one, that’s three total decimal places. Then, you take the total number of decimal places you counted and move the decimal point in your answer that many places to the left. This gives you the correct decimal answer for the multiplication.