Decimal Multiplication Practice Problems & Solutions

Master multiplying decimal numbers with step-by-step practice problems. Learn vertical multiplication method, decimal placement rules, and solve real examples.

📚Master Decimal Multiplication with Interactive Practice
  • Apply vertical multiplication method to decimal fraction problems
  • Count decimal places correctly to position decimal points in answers
  • Solve multiplication exercises with mixed whole numbers and decimals
  • Practice multiplying decimals with different numbers of decimal places
  • Master the five-step process for decimal multiplication accuracy
  • Build confidence with progressively challenging decimal multiplication problems

Understanding Multiplication of Decimal Fractions

Complete explanation with examples

We will solve the multiplication of decimal numbers using the vertical multiplication method.
We will proceed in the following order:

  • We will neatly write the multiplication exercise in vertical form – one decimal point under the other decimal point, tenths under tenths, hundredths under hundredths, etc.
  • We will solve the exercise and, for now, will not pay attention to the decimal point.
  • We will strictly adhere to the rules of vertical multiplication.
  • We will review each number in the exercise and find out how many digits there are after the decimal point.
  • We will count the total number of digits after the decimal point (taking into account both numbers) and that will be the number of digits after the decimal point in the final answer.
Detailed explanation

Practice Multiplication of Decimal Fractions

Test your knowledge with 11 quizzes

\( 0.01\times0.315= \)

Examples with solutions for Multiplication of Decimal Fractions

Step-by-step solutions included
Exercise #1

0.1×4.35= 0.1 \times 4.35 =

Step-by-Step Solution

To multiply 0.1 0.1 by 4.35 4.35 , move the decimal point in 4.35 4.35 one place to the left. Thus, 0.1×4.35=0.435 0.1 \times 4.35 = 0.435 .

Answer:

0.435 0.435

Exercise #2

0.1×0.008= 0.1 \times 0.008 =

Step-by-Step Solution

To multiply the decimal fractions 0.1 0.1 and 0.008 0.008 , first, ignore the decimal points and multiply the numbers as if they were whole numbers:

1×8=8 1 \times 8 = 8

Now, count the total number of decimal places in both of the original numbers. Here, 0.1 0.1 has 1 decimal place, and 0.008 0.008 has 3 decimal places, so there are 4 decimal places in total.

Thus, in the product, place the decimal point so that there are 4 digits to the right of the decimal point:

0.0008 0.0008

Answer:

0.0008 0.0008

Exercise #3

0.1×0.5= 0.1\times0.5=

Step-by-Step Solution

To solve this problem, we'll multiply the decimal numbers 0.10.1 and 0.50.5, following these steps:

  • Step 1: Treat each number as if it were a whole number and multiply: 1×5=51 \times 5 = 5.
  • Step 2: Count the decimal places in both factors. The number 0.10.1 has one decimal place, and 0.50.5 also has one decimal place.
  • Step 3: The total number of decimal places in the product should be the sum of the decimal places in the factors, which is 1+1=21 + 1 = 2.
  • Step 4: Place the decimal point in the product 55, resulting in 0.050.05, to ensure it has two decimal places.

Therefore, the product of 0.10.1 and 0.50.5 is 0.050.05.

Answer:

0.05 0.05

Video Solution
Exercise #4

0.1×0.35= 0.1\times0.35=

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Convert the decimal numbers into a form that is easier to multiply.
  • Step 2: Multiply the numbers as if they were whole numbers.
  • Step 3: Adjust the product by placing the decimal point correctly.

Now, let's work through each step:

Step 1: Convert the decimals 0.10.1 and 0.350.35 into whole number expressions:

  • 0.10.1 can be thought of as 110\frac{1}{10}.
  • 0.350.35 can be thought of as 35100\frac{35}{100}.

Step 2: Multiply as whole numbers: Multiply 11 and 3535 to obtain 3535.

Step 3: Adjust the decimal point:

  • 0.10.1 has 1 decimal place.
  • 0.350.35 has 2 decimal places.
Thus, their product should have 1+2=31 + 2 = 3 decimal places.

Therefore, the product of 0.10.1 and 0.350.35 is 0.0350.035.

Looking at the choices provided:

  • Choice 1: 0.350.35 is incorrect as it does not consider the decimal adjustment.
  • Choice 2: 0.0350.035 is correct.
  • Choice 3: 0.3500.350 is incorrect as it has an extra zero and maintains the incorrect placement of the decimal point.
  • Choice 4: 0.3100.310 is incorrect as it does not correspond with the straightforward multiplication of the operands.

Thus, the correct choice is 0.0350.035.

Answer:

0.035 0.035

Video Solution
Exercise #5

0.1×0.999= 0.1\times0.999=

Step-by-Step Solution

To solve 0.1×0.999 0.1 \times 0.999 , we need to follow these steps carefully:

  • Step 1: Treat the numbers as integers and multiply them. Ignoring the decimal points temporarily, multiply 1 1 by 999 999 :
    1×999=999\quad 1 \times 999 = 999.
  • Step 2: Determine the total number of decimal places in the factors.
    0.1\quad 0.1 has 1 decimal place.
    0.999\quad 0.999 has 3 decimal places.
    Therefore, the product should have 1+3=41 + 3 = 4 decimal places.
  • Step 3: Position the decimal in the product calculated in step 1.
    999\quad 999 with 4 decimal places becomes 0.09990.0999.

Therefore, the product of 0.1×0.999 0.1 \times 0.999 is 0.0999 0.0999 .

Answer:

0.0999 0.0999

Video Solution

Frequently Asked Questions

How do you multiply decimal numbers step by step?

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Follow these 5 steps: 1) Write numbers in vertical form aligning decimal points, 2) Multiply ignoring decimal points, 3) Apply vertical multiplication rules, 4) Count total decimal places in both numbers, 5) Place decimal point in answer with same total decimal places.

Where do you put the decimal point when multiplying decimals?

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Count the decimal places in both numbers being multiplied, then add them together. The answer should have the same total number of decimal places. For example, 0.4 × 0.2 has 1+1=2 decimal places, so the answer 0.08 has 2 decimal places.

What are common mistakes when multiplying decimal fractions?

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• Forgetting to count decimal places in both numbers • Misaligning decimal points in vertical setup • Not following vertical multiplication rules • Placing decimal point incorrectly in final answer • Rushing through the counting step

How do you multiply a whole number by a decimal?

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Use the same vertical multiplication method. Write the whole number above the decimal, multiply normally ignoring the decimal point, then count decimal places only in the decimal number. Place the decimal point in your answer accordingly.

Why do we ignore decimal points during multiplication?

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Ignoring decimal points initially simplifies the multiplication process by treating numbers as whole numbers. After completing the multiplication, we determine the correct decimal placement by counting total decimal places from the original numbers.

What is the vertical multiplication method for decimals?

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The vertical method involves: writing one decimal under another with decimal points aligned, multiplying as if they were whole numbers, following standard multiplication rules (carrying remainders, reserving spaces for zeros), then placing the decimal point based on total decimal places counted.

How many decimal places should 15.06 × 0.01 have?

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15.06 has 2 decimal places and 0.01 has 2 decimal places. Total: 2+2=4 decimal places. So 15.06 × 0.01 = 0.1506 (4 decimal places).

Can you multiply decimals without a calculator?

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Yes, using the vertical multiplication method makes it easy to multiply decimals by hand. The key is mastering whole number multiplication first, then applying the decimal placement rule by counting decimal places in both original numbers.

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