Examples with solutions for Multiplying and Dividing Decimal Fractions by 10, 100, etc.: Complete the missing numbers

Exercise #1

?×10=45 ?\times10=45

Video Solution

Step-by-Step Solution

To solve the problem ?×10=45? \times 10 = 45, we can use the following steps:

  • Step 1: Understand the equation (?×10=45)(? \times 10 = 45).
  • Step 2: Rearrange the equation to solve for the unknown: ?=4510? = \frac{45}{10}.
  • Step 3: Perform the division operation: 4510=4.5\frac{45}{10} = 4.5.

We divide 45 by 10 to find that the missing number is 4.5. Therefore, 4.5×10=454.5 \times 10 = 45.

Thus, the missing number in the equation is 4.5\boxed{4.5}.

From the given choices, the correct answer is 4.5\boxed{4.5}, which corresponds to choice 3.

Answer

4.5 4.5

Exercise #2

0.1×?=10 0.1\times?=10

Video Solution

Step-by-Step Solution

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

  • Step 1: Write down the given equation 0.1×?=100.1 \times ? = 10.
  • Step 2: Solve the equation by isolating ?'?' using division. We divide both sides of the equation by 0.10.1.

Let's work through these steps in detail:
Step 1: We have 0.1×?=100.1 \times ? = 10.
Step 2: To isolate ?'?', divide both sides of the equation by 0.10.1. This gives us ?=100.1? = \frac{10}{0.1}.
Calculating this division: ?=100.1=100? = \frac{10}{0.1} = 100.

Therefore, the solution to this problem is 100\boxdot 100, confirming the equivalence 0.1×100=100.1 \times 100 = 10.

Answer

100 100

Exercise #3

0.1×?=1 0.1\times?=1

Video Solution

Step-by-Step Solution

To solve this problem, we need to find out what number, when multiplied by 0.10.1, equals 11. This means setting up the equation 0.1×x=10.1 \times x = 1.

To isolate xx, rearrange the equation:
x=10.1 x = \frac{1}{0.1}

Next, perform the division 1÷0.11 \div 0.1. Dividing by a decimal is equivalent to multiplying by its reciprocal, thus:
10.1=1×10=10 \frac{1}{0.1} = 1 \times 10 = 10

Therefore, the solution to the equation is x=10 x = 10 .

Answer

10 10

Exercise #4

15.6:?=1.56 15.6:?=1.56

Video Solution

Step-by-Step Solution

To solve this problem, we need to determine the value that, when multiplied with 1.56, results in 15.6. Let's proceed with a step-by-step approach:

  • Step 1: Identify the task. We have the division relationship 15.6:x=1.56 15.6 : x = 1.56 , where x x is the missing number we want to find.
  • Step 2: Set up an equation based on this relationship: x=15.61.56 x = \frac{15.6}{1.56} .
  • Step 3: Perform the division. Convert 15.6 and 1.56 to eliminate decimals, facilitating easier division: - Multiply both numerator and denominator by 100 to make it an integer division: 15.6×1001.56×100=1560156\frac{15.6 \times 100}{1.56 \times 100} = \frac{1560}{156}.
  • Step 4: Simplify the fraction 1560156 \frac{1560}{156} : - Divide both numbers by the greatest common divisor, which is 156: 1560÷156156÷156=101=10 \frac{1560 \div 156}{156 \div 156} = \frac{10}{1} = 10 .
  • Step 5: Verify. Multiply 1.56 by 10 to check: 1.56×10=15.6 1.56 \times 10 = 15.6 , confirming our calculation.

Therefore, the solution to the problem is that the missing number is 10 10 .

Answer

10 10

Exercise #5

1.66:?=0.166 1.66:?=0.166

Video Solution

Step-by-Step Solution

To solve this problem, we'll use the equation 1.66÷x=0.166 1.66 \div x = 0.166 . This can be rewritten in terms of multiplication as:

  • x=1.660.166 x = \frac{1.66}{0.166}

Now, let's perform the division:

First, recognize that dividing by a decimal is equivalent to dividing their fractions:

  • 1.66=166100 1.66 = \frac{166}{100}
  • 0.166=1661000 0.166 = \frac{166}{1000}

Therefore, we have:

x=1.660.166=1661001661000 x = \frac{1.66}{0.166} = \frac{\frac{166}{100}}{\frac{166}{1000}}

Dividing these fractions is equivalent to multiplying by the reciprocal:

x=166100×1000166 x = \frac{166}{100} \times \frac{1000}{166}

Cancel out 166 166 in the numerator and denominator:

x=1000100=10 x = \frac{1000}{100} = 10

Therefore, the missing number x x is 10 \boxed{10} .

Answer

10 10

Exercise #6

5.2:?=0.52 5.2:?=0.52

Video Solution

Step-by-Step Solution

To find the value of '?', we'll set up the equation based on the division of numbers:

Given that 5.2÷?=0.52 5.2 \div ? = 0.52 , we can rewrite this equation as:

5.2=0.52×? 5.2 = 0.52 \times ?

To isolate the '?', we divide both sides of the equation by 0.52:

?=5.20.52 ? = \frac{5.2}{0.52}

Calculating this division gives us:

?=10 ? = 10

This means when 5.2 is divided by 10, the result is 0.52, confirming that '? = 10' is correct.

Therefore, the solution to the problem is 10 10 .

Answer

10 10

Exercise #7

?×10=3.3 ?\times10=3.3

Video Solution

Step-by-Step Solution

To find the missing number that, when multiplied by 10, equals 3.3, let's follow these steps:

  • Step 1: Start with the equation x×10=3.3 x \times 10 = 3.3 .

  • Step 2: To isolate x x , divide both sides of the equation by 10:

x=3.310 x = \frac{3.3}{10}

Step 3: Perform the division. Dividing 3.3 by 10 effectively shifts the decimal point one place to the left:

x=0.33 x = 0.33

Therefore, the solution to the equation is x=0.33 x = 0.33 .

This matches choice 4: 0.33 0.33 .

Answer

0.33 0.33

Exercise #8

?:100=0.0244 ?:100=0.0244

Video Solution

Step-by-Step Solution

To solve this problem, we need to find the value of x x in the equation:

x100=0.0244\frac{x}{100} = 0.0244

Let's follow these steps:

  • Step 1: Recognize that x100 \frac{x}{100} is equivalent to dividing x x by 100.

  • Step 2: To isolate x x , we need to perform the inverse operation of dividing by 100, which is multiplying by 100.

  • Step 3: Multiply both sides of the equation by 100.
    x100×100=0.0244×100 \frac{x}{100} \times 100 = 0.0244 \times 100

  • Step 4: Simplify the left-hand side to just x x , and calculate the right-hand side:
    x=2.44 x = 2.44

Thus, the value of x x that satisfies the equation is x=2.44 x = 2.44 .

Accordingly, the correct answer is the choice '2.44 2.44 '.

Answer

2.44 2.44

Exercise #9

?:100=0.0111 ?:100=0.0111

Video Solution

Step-by-Step Solution

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

  • Step 1: Start with the equation x100=0.0111 \frac{x}{100} = 0.0111 .
  • Step 2: Multiply both sides of the equation by 100 to isolate x x .

Now, let's work through each step:
Step 1: We have x100=0.0111 \frac{x}{100} = 0.0111 .
Step 2: To solve for x x , multiply both sides by 100:
(x=0.0111×100)(x = 0.0111 \times 100)

This simplifies to:
x=1.11x = 1.11

Therefore, the number that fits the equation is x=1.11 x = 1.11 .

Looking at the choices provided, the correct answer is 1.11 1.11 .

Answer

1.11 1.11

Exercise #10

12.33×?=1233 12.33\times?=1233

Video Solution

Step-by-Step Solution

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

  • Step 1: Identify the equation given in the problem
  • Step 2: Solve for the unknown variable x x

Now, let's work through each step:
Step 1: The problem asks us to find the value of x x in the equation 12.33×x=1233 12.33 \times x = 1233 .
Step 2: To isolate x x , divide both sides by 12.33:

x=123312.33 x = \frac{1233}{12.33}

Calculate the division:

x100 x \approx 100

Therefore, the solution to the problem is 100\boxed{100}. Given the multiple-choice options, the correct answer matches choice 2: 100 100 .

Answer

100 100

Exercise #11

52.3:?=0.523 52.3:?=0.523

Video Solution

Step-by-Step Solution

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

  • Step 1: Recognize the given expression as a division problem: 52.3:x=0.523 52.3 : x = 0.523 .
  • Step 2: Convert it into a multiplication equation: 52.3=0.523×x 52.3 = 0.523 \times x .
  • Step 3: Solve for x x . This means rearranging the equation: x=52.30.523 x = \frac{52.3}{0.523} .
  • Step 4: Perform the division to find x x .

Now, let's work through these steps:

Step 1: We start with 52.3:x=0.523 52.3 : x = 0.523 .

Step 2: By converting the division into multiplication, we have 52.3=0.523×x 52.3 = 0.523 \times x .

Step 3: Isolating x x , we rewrite this as x=52.30.523 x = \frac{52.3}{0.523} .

Step 4: Performing the division yields x=100 x = 100 .

Therefore, the solution to the problem is x=100 x = 100 .

Answer

100 100

Exercise #12

?×100=511 ?\times100=511

Video Solution

Step-by-Step Solution

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

  • Step 1: Identify the equation ?×100=511? \times 100 = 511.
  • Step 2: Solve for the unknown by using division.

Now, let's work through the solution:

Step 1: We start with the equation provided: ?×100=511? \times 100 = 511.

Step 2: To isolate the unknown, divide both sides of the equation by 100.
?=511100? = \frac{511}{100}

Performing the division, we have:
?=5.11? = 5.11

Therefore, the solution to the problem is 5.11 5.11 .

Answer

5.11 5.11