Arithmetic Grade Six

Lesson Seventy: Decimal Multiplication

The method used to solve decimal multiplication problems are the same. The only difference is that you have to know where to place the decimal point once you've completed your calculations. Consider this example. 

	    4.5
	  x .73
	 --------
	    135    <--- partial product one
	   315     <--- partial product two
	---------
	  3.285    <--- final product with decimal point
As you can see it is not necessary for you to even think about the decimal while calculating the partial products. It is not until you add up the final product that you have to worry about the decimal point. When doing this on paper, most people add up the final product and then squeeze the decimal point into the proper place.

Here's another example: 


	   .34
	 x .21
	--------
	    34		<--- partial product one
	   68		<--- partial product two
	--------	
	 .0714		<--- final product with decimal point

As you can see, sometimes you have to add a zero in front of the digits which you calculate in order to put the decimal point in the proper position.

Before going any further let's practice with some easy decimal multplication: 

 
	.09 x .4 = .036

	.03 x .02 = .0006

	.7 x .02 = .014

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