Examples with solutions for The Distributive Property for 7th Grade: Using fractions

Exercise #1

23(12+05)= \frac{2}{3}(12+0-5)=

Video Solution

Step-by-Step Solution

According to the distribution law rules, we will multiply both thirds by each term in parentheses:

23×12+23×023×5= \frac{2}{3}\times12+\frac{2}{3}\times0-\frac{2}{3}\times5=

Remember that any whole number can be written as a fraction with a denominator of 1, except for the digit 0.

Let's write the exercise in the following form:

23×121+23×023×51= \frac{2}{3}\times\frac{12}{1}+\frac{2}{3}\times0-\frac{2}{3}\times\frac{5}{1}=

We multiply numerator by numerator and denominator by denominator in each multiplication exercise.

Remember that when we multiply any number by 0, the result will be 0.

Therefore we get:

243+0103= \frac{24}{3}+0-\frac{10}{3}=

Let's solve the first fraction exercise, and simplify the remaining fraction to get the exercise:

8313=423 8-3\frac{1}{3}=4\frac{2}{3}

Answer

423 4\frac{2}{3}

Exercise #2

9×389= 9\times3\frac{8}{9}=

Video Solution

Step-by-Step Solution

We will use the distributive property of multiplication and break down the fraction into a subtraction exercise between a whole number and a fraction. This allows us to work with smaller numbers and simplify the operation

Reminder - The distributive property of multiplication allows us to break down the larger term in a multiplication problem into a sum or difference of smaller numbers, which makes multiplication easier and gives us the ability to solve the problem even without a calculator

9×(419)= 9\times(4-\frac{1}{9})=

We will use the distributive property formula a(b+c)=ab+ac a(b+c)=ab+ac

(9×4)(9×19)= (9\times4)-(9\times\frac{1}{9})=

Let's solve what's in the left parentheses:

9×4=36 9\times4=36

Note that in the right parentheses we can reduce 9 by 9 as follows:

9=91 9=\frac{9}{1}

91×19=9×11×9=99=11=1 \frac{9}{1}\times\frac{1}{9}=\frac{9\times1}{1\times9}=\frac{9}{9}=\frac{1}{1}=1

And we get the exercise:

361=35 36-1=35

And now let's see the solution centered:

9×389=9×(419)=(9×4)(9×19)=361=35 9\times3\frac{8}{9}=9\times(4-\frac{1}{9})=(9\times4)-(9\times\frac{1}{9})=36-1=35

Answer

35 35

Exercise #3

3×214= 3\times2\frac{1}{4}=

Video Solution

Step-by-Step Solution

We will use the distributive property of multiplication and separate the fraction into an addition exercise between fractions. This allows us to work with smaller numbers and simplify the operation

Reminder - The distributive property of multiplication allows us to break down the larger term in the multiplication exercise into a sum or difference of smaller numbers, which makes the multiplication operation easier and gives us the ability to solve the exercise without a calculator

3×(2+14)= 3\times(2+\frac{1}{4})=

We will use the distributive property formula a(b+c)=ab+ac a(b+c)=ab+ac

(3×2)(3×14)= (3\times2)-(3\times\frac{1}{4})=

Let's solve what's in the left parentheses:

3×2=6 3\times2=6

Let's solve what's in the right parentheses:

3=31 3=\frac{3}{1}

31×14=3×11×4=34 \frac{3}{1}\times\frac{1}{4}=\frac{3\times1}{1\times4}=\frac{3}{4}

And we get the exercise:

6+34=634 6+\frac{3}{4}=6\frac{3}{4}

And now let's see the solution centered:

3×214=3×(2+14)=(3×2)+(3×14)=6+34=634 3\times2\frac{1}{4}=3\times(2+\frac{1}{4})=(3\times2)+(3\times\frac{1}{4})=6+\frac{3}{4}=6\frac{3}{4}

Answer

634 6\frac{3}{4}

Exercise #4

5×313= 5\times3\frac{1}{3}=

Video Solution

Step-by-Step Solution

We will use the distributive property of multiplication and separate the fraction into an addition exercise between fractions. This allows us to work with smaller numbers and simplify the operation

Reminder - The distributive property of multiplication actually allows us to separate the larger term in the multiplication exercise into a sum or difference of smaller numbers, which makes the multiplication operation easier and gives us the ability to solve the exercise without a calculator

5×(3+13)= 5\times(3+\frac{1}{3})=

We will use the distributive property formula a(b+c)=ab+ac a(b+c)=ab+ac

(5×3)+(5×13)= (5\times3)+(5\times\frac{1}{3})=

Let's solve what's in the left parentheses:

5×3=15 5\times3=15

Let's solve what's in the right parentheses:

5=51 5=\frac{5}{1}

51×13=5×11×3=53 \frac{5}{1}\times\frac{1}{3}=\frac{5\times1}{1\times3}=\frac{5}{3}

And we get the exercise:

15+53=15+123=1623 15+\frac{5}{3}=15+1\frac{2}{3}=16\frac{2}{3}

And now let's see the solution centered:

5×313=5×(3+13)=(5×3)+(5×13)=15+53=15+123=1623 5\times3\frac{1}{3}=5\times(3+\frac{1}{3})=(5\times3)+(5\times\frac{1}{3})=15+\frac{5}{3}=15+1\frac{2}{3}=16\frac{2}{3}

Answer

1623 16\frac{2}{3}

Exercise #5

5(212+116+34)= 5\cdot\big(2\frac{1}{2}+1\frac{1}{6}+\frac{3}{4}\big)=

Video Solution

Step-by-Step Solution

Let's simplify this expression while following the order of operations which states that exponents come before multiplication and division, which come before addition and subtraction, and that parentheses come before all of these,

We'll start by simplifying the expression inside the parentheses.

In this expression, there are addition operations between mixed fractions, so in the first step we'll convert all mixed fractions in this expression to improper fractions.

We'll do this by multiplying the whole number by the denominator of the fraction, and adding the result to the numerator.

In the fraction's denominator (which is the divisor) - nothing will change of course.

We'll do this in the following way:

212=(2×2)+12=4+12=52 2\frac{1}{2}=\frac{(2\times2)+1}{2}=\frac{4+1}{2}=\frac{5}{2}

116=(1×6)+16=6+16=76 1\frac{1}{6}=\frac{(1\times6)+1}{6}=\frac{6+1}{6}=\frac{7}{6}

Now we'll get the exercise:

5(52+76+34) 5\cdot\big(\frac{5}{2}+\frac{7}{6}+\frac{3}{4}\big)

We'll continue and perform the addition of fractions in the expression inside the parentheses.

First, we'll expand each fraction to the common denominator, which is 12 (since it is the least common multiple of all denominators in the expression), we'll do this by multiplying the numerator of the fraction by the number that answers the question: "By how much did we multiply the current denominator to get the common denominator?"

Then we'll perform the addition operations between the expanded numerators:

5(52+76+34)=556+72+3312=530+14+912=55312= 5\cdot\big(\frac{5}{2}+\frac{7}{6}+\frac{3}{4}\big) =\\ 5\cdot\frac{5\cdot6+7\cdot2+3\cdot3}{12} =\\ 5\cdot\frac{30+14+9}{12} =\\ 5\cdot\frac{53}{12} =\\ We performed the addition operation between the numerators above, after expanding the fractions mentioned.

Note that since multiplication comes before addition, we first performed the multiplications in the fraction's numerator and only then the addition operations,

We'll continue and simplify the expression we got in the last step, meaning - we'll perform the multiplication we got, while remembering that multiplying a fraction means multiplying the fraction's numerator.

In the next step, we'll write the result as a mixed fraction, we'll do this by finding the whole numbers (the answer to the question "How many complete times does the denominator go into the numerator?") and adding the remainder divided by the divisor:

55312=55312=26512=22112 5\cdot\frac{53}{12}=\\ \frac{5\cdot53}{12}=\\ \frac{265}{12}=\\ 22\frac{1}{12}

Let's summarize the steps of simplifying the given expression:

5(212+116+34)=5(52+76+34)=556+72+3312=55312=22112 5\cdot\big(2\frac{1}{2}+1\frac{1}{6}+\frac{3}{4}\big)= \\ 5\cdot\big(\frac{5}{2}+\frac{7}{6}+\frac{3}{4}\big)=\\ 5\cdot\frac{5\cdot6+7\cdot2+3\cdot3}{12} =\\ 5\cdot\frac{53}{12} =\\ 22\frac{1}{12}

Therefore the correct answer is answer B.

Answer

22112 22\frac{1}{12}

Exercise #6

Solve the following expression:

13(9234)= \frac{1}{3}(\frac{9}{2}-\frac{3}{4})=

Video Solution

Step-by-Step Solution

According to the order of operations rules, we will first address the expression in parentheses.

The common denominator between the fractions is 4, so we will multiply each numerator by the number needed for its denominator to reach 4.

We will multiply the first fraction's numerator by 2 and the second fraction's numerator by 1:

(9234)=2×91×34=1834=154 (\frac{9}{2}-\frac{3}{4})=\frac{2\times9-1\times3}{4}=\frac{18-3}{4}=\frac{15}{4}

Now we have the expression:

13×154= \frac{1}{3}\times\frac{15}{4}=

Note that we can reduce 15 and 3:

11×54= \frac{1}{1}\times\frac{5}{4}=

Now we multiply numerator by numerator and denominator by denominator:

1×51×4=54=114 \frac{1\times5}{1\times4}=\frac{5}{4}=1\frac{1}{4}

Answer

114 1\frac{1}{4}

Exercise #7

Solve the following expression:

x(13+12)= x(\frac{1}{3}+\frac{1}{2})=

Video Solution

Step-by-Step Solution

According to the order of operations rules, we will first address the expression in parentheses.

The common denominator between the fractions is 6, so we will multiply each numerator by the number needed to make its denominator reach 6.

We will multiply the first fraction's numerator by 2 and the second fraction's numerator by 3:

(13+12)=1×2+1×36=2+36=56 (\frac{1}{3}+\frac{1}{2})=\frac{1\times2+1\times3}{6}=\frac{2+3}{6}=\frac{5}{6}

Now we have the expression:

x×56= x\times\frac{5}{6}=

We will use the distributive property and get the result:

56x \frac{5}{6}x

Answer

56x \frac{5}{6}x

Exercise #8

(13+911)×33= (\frac{1}{3}+\frac{9}{11})\times33=

Video Solution

Step-by-Step Solution

We'll use the distributive property and multiply 33 by each term in the parentheses:

(13×33)+(91×33)= (\frac{1}{3}\times33)+(\frac{9}{1}\times33)=

Let's solve the left parentheses. Remember that:

33=331 33=\frac{33}{1}

13×331=1×333×1=333 \frac{1}{3}\times\frac{33}{1}=\frac{1\times33}{3\times1}=\frac{33}{3}

Now let's address the right parentheses, where we'll break down 33 into a smaller multiplication exercise that will help us later with reduction:

(911×33)=(911×11×3) (\frac{9}{11}\times33)=(\frac{9}{11}\times11\times3)

Now we'll reduce the 11 in the numerator and the 11 in the multiplication exercise and get:

333+9×3= \frac{33}{3}+9\times3=

Let's solve the fraction:

333=11 \frac{33}{3}=11

Now we'll get the exercise:

11+(9×3)= 11+(9\times3)=

According to the order of operations, we'll solve what's in the parentheses and get:

11+27=38 11+27=38

Answer

38 38

Exercise #9

10(0.75+1.2)= 10(0.75+1.2)=

Video Solution

Step-by-Step Solution

First, let's solve what's in the parentheses vertically.

Let's remember that:

1.2=1.20 1.2=1.20

We'll make sure to write the exercise correctly.

Note that the decimal point is in place and ones are under ones, tens under tens, etc.

1.20+0.75 1.20\\+0.75\\

And we'll get the result:

1.95 1.95

Now we have the exercise:

10×1.95= 10\times1.95=

This exercise doesn't require calculation, but rather moving the decimal point "one step" to the right, since we are multiplying by ten.

In other words, if we move the decimal point to the right we'll get:

19.5 19.5

Answer

19.5 19.5

Exercise #10

(13+512)×24= (\frac{1}{3}+\frac{5}{12})\times24=

Video Solution

Step-by-Step Solution

We'll use the distributive property and multiply 24 by each term in parentheses:

(13×24)+(512×24)= (\frac{1}{3}\times24)+(\frac{5}{12}\times24)=

Let's solve the left parentheses. Remember that:

24=241 24=\frac{24}{1}

13×241=1×243×1=243 \frac{1}{3}\times\frac{24}{1}=\frac{1\times24}{3\times1}=\frac{24}{3}

Now let's look at the right parentheses, where we'll split 24 into a smaller multiplication exercise that will help us later with reduction:

(512×24)=(512×12×2) (\frac{5}{12}\times24)=(\frac{5}{12}\times12\times2)

Now we'll reduce the 12 in the numerator and the 12 in the multiplication exercise and get:

243+5×2= \frac{24}{3}+5\times2=

Let's solve the fraction:

243=8 \frac{24}{3}=8

Now we'll get the exercise:

8+(5×2)= 8+(5\times2)=

According to the order of operations, we'll solve what's in the parentheses and get:

8+10=18 8+10=18

Answer

18 18

Exercise #11

Solve the following expression:

9(13+14)= 9(\frac{1}{3}+\frac{1}{4})=

Video Solution

Step-by-Step Solution

We'll use the distributive property and multiply 9 by each term in the parentheses:

(9×13)+(9×14)= (9\times\frac{1}{3})+(9\times\frac{1}{4})=

Let's solve the left parentheses. Remember that:

9=91 9=\frac{9}{1}

91×13=9×11×3=93 \frac{9}{1}\times\frac{1}{3}=\frac{9\times1}{1\times3}=\frac{9}{3}

Let's solve the right parentheses.

91×14=9×11×4=94 \frac{9}{1}\times\frac{1}{4}=\frac{9\times1}{1\times4}=\frac{9}{4}

Now we have the expression:

93+94= \frac{9}{3}+\frac{9}{4}=

Let's solve the left fraction:

93=3 \frac{9}{3}=3

For the right fraction, we'll separate the numerator into an addition problem:

94=8+14 \frac{9}{4}=\frac{8+1}{4}

We'll separate the fraction we got into an addition of fractions and get the expression:

3+84+14= 3+\frac{8}{4}+\frac{1}{4}=

Let's solve the fraction:

84=2 \frac{8}{4}=2

And now we obtain:

3+2+14=514 3+2+\frac{1}{4}=5\frac{1}{4}

Answer

514 5\frac{1}{4}