Multiplying Decimals

Now that we’ve learned adding and subtracting decimals, it’s time for the multiplication part of it. Multiplying decimals shouldn’t be too hard because the process is almost the same as multiplying whole numbers. The only difference is again, the placement of the decimal point. Don’t worry though, this free CSC Exam Reviewer will also explain how to deal with these kinds of computations. Onto an example of a decimal multiplication;

5.03 × 4.1

Unlike in addition and subtraction, the decimal point in this process becomes temporarily irrelevant. In solving the sample equation above, you have to write it down first without the decimal points. So 5.03 will become 503 and 4.1 will become 41. It should look like this when the decimal points are removed so that you won’t get confused;

503

×  41

Looks like your regular multiplication problem, right? Second step is to obviously, solve it. Don’t forget to align those digits properly.

503

×  41

503

+  2012

20623

 

We now have the solution but we’re not quite finished yet. Remember those decimal points? Now we have to determine where to put it in our answer. 5.03 has TWO DECIMAL PLACES and 4.1 has ONE DECIMAL PLACE. By adding those, we see that we have to put the decimal point three places to the left. What am I talking about? Take a look at the image below.

When counting decimal places, ALWAYS START FROM THE RIGHT SIDE OF THE LAST DIGIT to where the actual decimal point is. As you can see, we started counting from the right to the left of the “3” so there are two decimal places in 5.03 and only one in 4.1.

 

This is how your solution should look like when finished;

503

× 41

503

+  2012

20.623

To recap, when multiplying decimals;

First, ignore the decimal points.

Then solve it like you would a regular multiplication problem.

After that, add the number of decimal places of both the multiplicand and multiplier.

Finally, put the decimal point in its proper place.

 

So there, I hope the example above helped you learn more about the basics of multiplying decimals. With that out of the way, let’s proceed to some CSC Reviewer exercises pertaining to decimal multiplication. Have your scratch paper with you ready because you will need them.

CSC Exam Reviewer: Multiplication of Decimals

1. 10.9 × 2.8 = ___

1. 28.80      b. 30.52      c. 36.60      d. 42.30

2. 8 × 3.7 = ___

1. 29.6      b. 33.9      c. 39.3      d. 42.1

3. 5.8 × 2.7 = ___

1. 60.66      b. 45.66      c. 30.66      d. 15.66

4. 9.6 × 3.2 = ___

1. 21.12      b. 25.80      c. 28.27      d. 30.72

5. 9 × 0.7 = ___

1. 6.9      b. 9.70      c. 6.3      d. 9.07

6. 10.01 × 1.2 = ___

1. 12.210      b. 21.102      c. 12.012      d. 21.210

7. 5 × 0.8 = ___

1. 4      b. 4.4      c. 4.04      d. 4.44

8. 1.3 × 3 = ___

1. 9.3      b. 3.9      c. 6.3      d. 3.6

9. 6 × 1.8 = ___

1. 10.8      b. 8.6      c. 8.8      d. 10.6

10. 0.5 × 2.8 = ___

1. 1.8      b. 2.4      c. 1.4      d. 2.8

11. 9.4 × 5.1 = ___

1. 45.49      b. 49.74      c. 54.49      47.94

12. 6 × 0.2 = ___

1. 6.0      b. 1.2      c. 6.2      d. 1.0

13. 10.4 × 0.9 = ___

1. 12.36      b. 9.63      c. 9.36      d. 12.63

14. 4.2 × 1.8 = ___

1. 7.56      b. 8.65      c. 9.56      d. 10.65

15. 1.3 × 2.5 = ___

1. 3.25      b. 3.35      c. 3.45      d. 3.55

16. 4 × 0.1 = ___

1. 1.0      b. 0.4      c. 4.1      d. 1.4

17. 6.0 × 0.8 = ___

1. 4.4      b. 8.8     c. 4.8      d. 8.4

18. 26 × 1.05 = ___

1. 33.2      b. 31.9      c. 29.6      d. 27.3

19. 17.0 × 3.07 = ___

1. 46.49      b. 49.29      c. 52.19      d. 55.39

20. 14.9 × 2.09 = ___

1. 31.141      b. 31.441      c. 31.144      d. 31.414

21. 85.7 × 23.4 = ___

1. 2005.38      b. 2050.38      c. 2503.08      d. 2530.80

22. 67.23 × 18.18 = ___

1. 1,000.2441      b. 1,111.4214      c. 1,222.2414      d. 1,333.1424

23. 43.27 × 17.6 = ___

1. 865.362      b. 761.552      c. 855.842      d. 769.252

24. 18.537 × 8.7698 = ___

1. 162.2667558      b. 162.8557626      c. 162.6558762      d. 162.5657826

25. 17.9763 × 14.8519 = ___

1. 435.78922787      b. 266.82927797      c. 266.29897707      d. 266.98220997

Once you are finished, you can reveal the answers by clicking any of the buttons below and see how many right answers you were able to get.

So how many correct answers were you able to get? If it’s 18, then you did well, very good if around 15 or 16 and I would suggest you try again answering the CSC Multiplying Decimals Exercises if you only got 14 and below. Practice makes us better, you know.