Multiplying and Dividing Decimal Fractions by 10, 100, etc.: Multiplication by numbers greater than 100

Examples with solutions for Multiplying and Dividing Decimal Fractions by 10, 100, etc.: Multiplication by numbers greater than 100

Exercise #1

0.15×200= 0.15\times200=

Video Solution

Step-by-Step Solution

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

  • Step 1: Convert the multiplication into a simpler operation by treating decimals appropriately.
  • Step 2: Perform the multiplication.
  • Step 3: Adjust the result for decimal placement.

Now, let's work through each step:
Step 1: We need to find the result of multiplying 0.150.15 by 200200.
Step 2: Multiply as if 0.150.15 is 1515, then apply appropriate scaling for the decimal places:
15×200=3000 15 \times 200 = 3000
Step 3: Since 0.150.15 has two decimal places, divide the result by 100100:
3000100=30 \frac{3000}{100} = 30

Therefore, the solution to the problem is 30 30 .

Answer

30 30

Exercise #2

1.23×180= 1.23\times180=

Video Solution

Step-by-Step Solution

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

  • Step 1: Multiply the numbers.
  • Step 2: Consider the decimal places.

Let's go through each step:
Step 1: We start by calculating the product of 1.23 1.23 and 180 180 . Multiplying the numbers without considering the decimal initially, we treat it as 123×180 123 \times 180 .
Step 2: Calculate 123×180 123 \times 180 . This can be split into simpler calculations, 123×(100+80) 123 \times (100 + 80) :
- 123×100=12300 123 \times 100 = 12300
- 123×80=9840 123 \times 80 = 9840
Adding these: 12300+9840=22140 12300 + 9840 = 22140 .
Since 1.23 1.23 has two decimal places, we place the decimal point back in the product, which gives us 221.40 221.40 , or simplified, 221.4 221.4 .

Therefore, the solution to the problem is 221.4 221.4 .

Answer

221.4 221.4

Exercise #3

0.4×115= 0.4\times115=

Video Solution

Step-by-Step Solution

To solve this problem, we need to calculate the product of 0.40.4 and 115115.

First, let's perform the multiplication:

Multiply 115115 by 0.40.4:

115×0.4=46 115 \times 0.4 = 46

Here's how the calculation works step-by-step:

  • Consider 0.40.4 as 410\frac{4}{10}.
  • Therefore, the multiplication becomes 115×410115 \times \frac{4}{10}.
  • Perform the multiplication first: 115×4=460115 \times 4 = 460.
  • Then divide by 1010 to manage the decimal place:46010=46 \frac{460}{10} = 46.

Thus, the solution to the problem is 4646.

Answer

46 46

Exercise #4

1.23×110= ? 1.23\times110=\text{ ?}

Video Solution

Step-by-Step Solution

We will use the distributive property to split 110 into two numbers—100 and 10. 

Now we will multiply the original number (1.23) by these two numbers:

1.23*100=123

1.23*10=12.3

 

All that is left to do is to add the two products together to get our answer:

123 + 12.3 = 135.3

Answer

135.3 135.3

Exercise #5

14.6×150= 14.6\times150=

Video Solution

Step-by-Step Solution

To solve this problem, we'll proceed with these steps:

  • Step 1: Multiply 146 by 150, ignoring the decimal point initially.
  • Step 2: Adjust for the decimal point after completing the multiplication.

Step 1: Consider 14.6 as 146, so multiply 146 by 150:

  • First, multiply 146 by 10: 146×10=1460146 \times 10 = 1460.
  • Next, multiply 1460 by 15. We can break this into smaller steps:
  • 1460×151460 \times 15 can be computed as (1460×10)+(1460×5)(1460 \times 10) + (1460 \times 5).
  • 1460×10=146001460 \times 10 = 14600.
  • 1460×5=73001460 \times 5 = 7300.
  • Add these products: 14600+7300=2190014600 + 7300 = 21900.

Step 2: Since we treated 14.6 as 146 (multiplied by 10 initially), divide the result by 10:

  • 21900÷10=219021900 \div 10 = 2190.

Therefore, the product of 14.6×15014.6 \times 150 is 21902190.

Answer

2190 2190

Exercise #6

0.113×170= 0.113\times170=

Video Solution

Step-by-Step Solution

To solve this problem, we'll use straightforward multiplication while carefully considering the decimal place. Here are the steps we'll follow:

  • Step 1: Treat 0.113 0.113 as 113 113 by ignoring the decimal point temporarily.

  • Step 2: Multiply 113×170 113 \times 170 .

  • Step 3: Reintroduce the decimal point in the product by placing it three decimal places from the right, as in 0.113 0.113 .

Let's work through each step:

Step 1: We rewrite 0.113 0.113 as 113 113 .

Step 2: Multiplying 113 113 by 170 170 yields:

113×170amp;=113×(100+70)amp;=113×100+113×70amp;=11300+7910amp;=19210 \begin{aligned} 113 \times 170 &= 113 \times (100 + 70)\\ &= 113 \times 100 + 113 \times 70\\ &= 11300 + 7910\\ &= 19210 \end{aligned}

Step 3: Now place the decimal point. Since the original number 0.113 0.113 had three decimal places, the product 19210 19210 must be adjusted to three decimal places from the right, yielding:

19.210 \begin{aligned} 19.210 \end{aligned}

Thus, the final answer is:

19.21 19.21

Answer

19.21 19.21

Exercise #7

5.11×110= 5.11\times110=

Video Solution

Step-by-Step Solution

To solve this problem, we'll multiply the decimal number 5.11 by the integer 110. To do this, we'll follow these main steps:

  • Step 1: Treat the decimal number 5.11 temporarily as 511 by ignoring the decimal point. This helps us simplify the multiplication process.
  • Step 2: Multiply 511 by 110, as if they were whole numbers:

511×110 511 \times 110

  • Step 3: Calculate the product:

511×110=56210 511 \times 110 = 56210

  • Step 4: Since the original problem involved a decimal (two decimal places in number 5.11), adjust the product to account for these two decimal places by dividing by 100:

56210÷100=562.1 56210 \div 100 = 562.1

Therefore, the solution to the problem is 562.1 562.1 .

Answer

562.1 562.1

Exercise #8

3.12×109= 3.12\times109=

Video Solution

Step-by-Step Solution

To solve 3.12×1093.12 \times 109, we proceed as follows:

  • Step 1: Multiply the numbers as if they were whole numbers. Multiply 312312 by 109109.
  • Step 2: Calculate 312×109312 \times 109:
    • 312×100=31200312 \times 100 = 31200
    • 312×9=2808312 \times 9 = 2808
    • Add the two results: 31200+2808=3400831200 + 2808 = 34008.
  • Step 3: Adjust for decimal places. Since 3.123.12 has two decimal places, divide 3400834008 by 100100 to get 340.08340.08.

Therefore, the solution to the multiplication is 340.08340.08.

Answer

340.08 340.08

Exercise #9

11.2×101= 11.2\times101=

Video Solution

Step-by-Step Solution

To solve this problem, we'll use the distributive property of multiplication:

  • Step 1: Decompose 101 101 into 100+1 100 + 1 .
  • Step 2: Apply the distributive property: 11.2×(100+1)=(11.2×100)+(11.2×1) 11.2 \times (100 + 1) = (11.2 \times 100) + (11.2 \times 1) .
  • Step 3: Calculate 11.2×100 11.2 \times 100 and 11.2×1 11.2 \times 1 , then add the results.

Now, let's execute each step:
Step 1: Write 101 101 as 100+1 100 + 1 .
Step 2: Use the distributive property:
11.2×101=11.2×(100+1)=(11.2×100)+(11.2×1) 11.2 \times 101 = 11.2 \times (100 + 1) = (11.2 \times 100) + (11.2 \times 1) .

Step 3: Perform each multiplication:
11.2×100=1120 11.2 \times 100 = 1120 .
11.2×1=11.2 11.2 \times 1 = 11.2 .

Adding the results: 1120+11.2=1131.2 1120 + 11.2 = 1131.2 .

Thus, the product of 11.2×101 11.2 \times 101 is 1131.2 1131.2 , which matches the correct choice from the provided list.

Answer

1131.2 1131.2