Examples with solutions for All Operations in the Order of Operations: Using negative numbers

Exercise #1

Solve the following equation:

[(15×8+15) ⁣:27+45]×8 ⁣:205= \frac{\lbrack(15\times8+15)\colon27+45\rbrack\times8\colon20}{-5}=

Video Solution

Step-by-Step Solution

Initially, we address the first parentheses in the numerator of the fraction:

(15×8+15)= (15\times8+15)=

According to the rules, we first must solve the multiplication exercise and then the addition:

120+15=135 120+15=135

We obtain the following exercise:

(135:27+45)×8:205= \frac{(135:27+45)\times8:20}{-5}=

We will again address the parentheses in the numerator of the fraction. First by solving the division and then addition exercise.

5+45=50 5+45=50

We are left with the following exercise:

50×8:205= \frac{50\times8:20}{-5}=

We divide 50 into a multiplication exercise:

5×10×8:205= \frac{5\times10\times8:20}{-5}=

We then simplify:

10×8:20= -10\times8:20=

Lastly we solve from left to right:

80:20=4 -80:20=-4

Answer

4-

Exercise #2

Solve the following equation:

400 ⁣:(5)[2(9361)]4= \frac{400\colon(-5)-\lbrack-2(93-61)\rbrack}{4}=

Video Solution

Step-by-Step Solution

We begin by addressing the numerator of the fraction.

First we solve the division exercise and the exercise within the parentheses:

400:(5)=80 400:(-5)=-80

(9361)=32 (93-61)=32

We obtain the following:

80(2×32)4= \frac{-80-(-2\times32)}{4}=

We then solve the parentheses in the numerator of the fraction:

80(64)4= \frac{-80-(-64)}{4}=

Let's remember that a negative times a negative equals a positive:

80+644= \frac{-80+64}{4}=

164=4 \frac{-16}{4}=-4

Answer

4 -4

Exercise #3

Solve the following equation:

(32×4+8) ⁣:(27+35)2= \frac{(32\times4+8)\colon(-27+35)}{-2}=

Video Solution

Step-by-Step Solution

We begin by solving the two parentheses in the numerator of the fraction:

(32×4+8)=128+8=136 (32\times4+8)=128+8=136

(27+35)=8 (-27+35)=8

We obtain the following exercise:

136:82= \frac{136:8}{-2}=

172=8.5 \frac{17}{-2}=-8.5

Answer

-8.5

Exercise #4

Solve the following equation:

9(153[1714]+4)+12 ⁣:3×7= -9-(15-3-\lbrack17-14\rbrack+4)+12\colon3\times7=

Video Solution

Step-by-Step Solution

According to the order of arithmetic operations, we begin by solving the innermost parenthesis and the division exercise first:

9(1533+4)+4×7= -9-(15-3-3+4)+4\times7=

We then solve the parenthesis exercise from left to right:

1533+4=123+4=9+4=13 15-3-3+4=12-3+4=9+4=13

We obtain the following exercise:

913+(4×7)= -9-13+(4\times7)=

We then solve the multiplication exercise and obtain:

913+28= -9-13+28=

Lastly we solve the exercise from left to right:

913=22 -9-13=-22

22+28=6 -22+28=6

Answer

6

Exercise #5

6×15142714+20 ⁣:5= 6\times15-142-\frac{7}{14}+20\colon5=

Video Solution

Step-by-Step Solution

According to the order of operations, first we solve the multiplication and division exercises.

We will put them in parentheses to avoid confusion later in the solution:

(6×15)142714+(20:5)= (6\times15)-142-\frac{7}{14}+(20:5)=

We solve the exercises in parentheses:

90142714+4= 90-142-\frac{7}{14}+4=

We will rewrite the denominator of the fraction as a multiplication exercise:

9014277×2+4= 90-142-\frac{7}{7\times2}+4=

We simplify and obtain:

9014212+4= 90-142-\frac{1}{2}+4=

Now we solve the exercise from left to right:

5212+4= -52-\frac{1}{2}+4=

5212+4=4812 -52\frac{1}{2}+4=-48\frac{1}{2}

Answer

-48.5