Examples with solutions for Addition and Subtraction of Directed Numbers: Solving the problem

Exercise #1

(+567)(69)= (+567)-(-69)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

(x)=+x -(-x)=+x

Now let's write the exercise in the appropriate form:

567+69= 567+69=

Let's solve the exercise vertically:

567+69636 567\\+69\\636

Answer

636 636

Exercise #2

Solve the following problem

(+6)(+11)= (+6)-(+11)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

(+x)=x -(+x)=-x

Now let's write the exercise in the appropriate form:

611= 6-11=

We'll locate the number 6 on the number line and from there we'll move 11 steps to the left:

111-2-2-2-1-1-1000-3-3-3-4-4-4666222333444555-5-5-5

The answer is minus 5.

Answer

5 -5

Exercise #3

Solve the following equation:

(8)+(+12)= ? (-8)+(+12)=\text{ ?}

Video Solution

Step-by-Step Solution

First, let's remember the rule:

+(+x)=+x +(+x)=+x

Now let's write the exercise in the following way:

8+12= -8+12=

We'll draw a number line and place minus 8 on it, then move 12 steps to the right:

-1-1-1-4-4-4-3-3-3-2-2-2-5-5-5-6-6-6-8-8-8-7-7-7444000111222333

Therefore:

8+12=4 -8+12=4

Answer

4 4

Exercise #4

(8)+(12)= (-8)+(-12)=

Video Solution

Step-by-Step Solution

Let's locate -8 on the number line and move 12 steps to the left.

Let's note that our result is a negative number:

000-8-8-8-12

Let's remember the rule:

Now let's write the exercise in the appropriate form and solve it:

812=20 -8-12=-20

Answer

20 -20

Exercise #5

(8)(13)= (-8)-(-13)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

(x)=+x -(-x)=+x

Now let's write the exercise in the appropriate form:

8+13= -8+13=

We'll use the substitution law and solve:

138=5 13-8=5

Answer

5 5

Exercise #6

Solve the following expression:

(+8)+(4.5)= ? (+8)+(-4.5)=\text{ ?}

Video Solution

Step-by-Step Solution

First we need to locate the number 8 on the number line and move 4.5 steps to the left from it:

000888

Remember the rule:

+(x)=x +(-x)=-x

Now let's rewrite the problem in the appropriate form and solve:

84.5=3.5 8-4.5=3.5

Answer

3.5 3.5

Exercise #7

Solve the following expression:

(+8)+(+12)= ? (+8)+(+12)=\text{ ?}

Video Solution

Step-by-Step Solution

Let's add 8 to the number line and move 12 steps to the right.

Note that our result is a positive number:

Now solve the following exercise:

8+12=20 8+12=20

Answer

20 20

Exercise #8

(+301)+(51)= ? (+301)+(-51)=\text{ ?}

Video Solution

Step-by-Step Solution

First, remember the rule:

+(x)=x +(-x)=-x

Place 301 on the number line and move 51 steps to the left:

000301301301-51

Rewrite the exercise in the appropriate form and solve it:

30151=250 301-51=250

Answer

250 250

Exercise #9

(10)(+13)= (-10)-(+13)=

Video Solution

Step-by-Step Solution

Let's locate -10 on the number line and move 13 steps to the left.

Let's note that our result is a negative number:

000-10-10-10-13

Let's remember the rule:

(+x)=x -(+x)=-x

Now let's write the exercise in the appropriate form and solve it:

1013=23 -10-13=-23

Answer

23 -23

Exercise #10

Solve the following exercise:

(17)(77)= (-\frac{1}{7})-(-\frac{7}{7})=

Step-by-Step Solution

Let's position minus 17 \frac{1}{7} on the number line and move one step to the right, since 77=11=1 \frac{7}{7}=\frac{1}{1}=1

We should note that our result is a positive number:

000+1

Let's remember the rule:

(x)=+x -(-x)=+x

Now let's write the exercise in the appropriate form and solve it:

17+1=67 -\frac{1}{7}+1=\frac{6}{7}

Answer

67 \frac{6}{7}

Exercise #11

(+1213)+(+814)= (+12\frac{1}{3})+(+8\frac{1}{4})=

Video Solution

Step-by-Step Solution

To solve this problem, we will proceed as follows:

  • Step 1: Identify the whole number and fractional parts of each mixed number.
  • Step 2: Add the whole numbers separately.
  • Step 3: Add the fractions by first finding a common denominator.
  • Step 4: Combine the sums from Steps 2 and 3.

Now, let's work through the solution:

Step 1:
Extract the whole numbers and fractions:
+1213 +12\frac{1}{3} has a whole number 12 and a fraction 13\frac{1}{3}.
+814 +8\frac{1}{4} has a whole number 8 and a fraction 14\frac{1}{4}.

Step 2:
Add the whole numbers:
12 + 8 = 20.

Step 3:
Add the fractions by finding a common denominator. The fractions are 13\frac{1}{3} and 14\frac{1}{4}.
- The least common denominator of 3 and 4 is 12.
- Convert 13\frac{1}{3} to 412\frac{4}{12}.
- Convert 14\frac{1}{4} to 312\frac{3}{12}.

Add the fractions now:
412+312=712\frac{4}{12} + \frac{3}{12} = \frac{7}{12}.

Step 4:
Combine the sums from Steps 2 and 3:
The sum of the whole numbers is 20, and the sum of the fractions is 712\frac{7}{12}.
Thus, +1213++814=20712 +12\frac{1}{3} + +8\frac{1}{4} = 20\frac{7}{12} .

Therefore, the solution to the problem is 20712 20\frac{7}{12} .

Answer

20712 20\frac{7}{12}

Exercise #12

(1314)+(927)= (-13\frac{1}{4})+(-9\frac{2}{7})=

Video Solution

Step-by-Step Solution

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

  • Step 1: Convert mixed numbers to improper fractions.
  • Step 2: Find the least common denominator.
  • Step 3: Perform the addition and convert back to a mixed number.

Let's work through each step:

Step 1: Convert mixed numbers to improper fractions.

1314 -13\frac{1}{4} = (13+14)=(524+14)=534 -\left( 13 + \frac{1}{4} \right) = -\left( \frac{52}{4} + \frac{1}{4} \right) = -\frac{53}{4}

927 -9\frac{2}{7} = (9+27)=(637+27)=657 -\left( 9 + \frac{2}{7} \right) = -\left( \frac{63}{7} + \frac{2}{7} \right) = -\frac{65}{7}

Step 2: Determine a common denominator. The least common multiple of 4 and 7 is 28.

Convert the fractions:

534=53×74×7=37128 -\frac{53}{4} = -\frac{53 \times 7}{4 \times 7} = -\frac{371}{28}

657=65×47×4=26028 -\frac{65}{7} = -\frac{65 \times 4}{7 \times 4} = -\frac{260}{28}

Step 3: Add the fractions:

37128+(26028)=371+26028=63128 -\frac{371}{28} + \left(-\frac{260}{28}\right) = -\frac{371 + 260}{28} = -\frac{631}{28}

Converting 63128 -\frac{631}{28} back to a mixed number:

Perform the division: 631÷2822 631 \div 28 \approx 22 remainder 15.

This gives us a mixed number: 221528 -22\frac{15}{28}

Therefore, the solution to the problem is 221528 -22\frac{15}{28} .

Answer

221528 -22\frac{15}{28}

Exercise #13

(+14)+(234)= ? (+\frac{1}{4})+(2\frac{3}{4})=\text{ ?}

Video Solution

Step-by-Step Solution

First, locate the number 14 \frac{1}{4} on the number line and move 234 2\frac{3}{4} steps to the right from it.

This means the resulting number will be positive:

Finally, solve the exercise:

14+234=3 \frac{1}{4}+2\frac{3}{4}=3

Answer

3

Exercise #14

(+0.18)+(+0.88)= (+0.18)+(+0.88)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

+(+x)=+x +(+x)=+x

Now let's write the exercise in the following way:

0.18+0.88= 0.18+0.88=

Since we are multiplying two positive numbers, the result will be positive.

Therefore:

0.18+0.881.06 0.18\\+0.88\\1.06

Answer

1.06 1.06

Exercise #15

(0.73)+(13.07)= (-0.73)+(-13.07)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

+(x)=x +(-x)=-x

Now let's write the exercise in the appropriate form:

0.7313.07= -0.73-13.07=

Since we are subtracting a larger number from a smaller number, the result will be negative.

We'll combine the two numbers together vertically, but remember that the result will be negative:

0.73+13.0713.80 0.73\\+13.07\\13.80

Therefore, the answer is:

0.7313.07=13.8 -0.73-13.07=-13.8

Answer

13.8 -13.8

Exercise #16

(0.43)(0.87)= (-0.43)-(-0.87)=

Video Solution

Step-by-Step Solution

Let's first consider the rule:

(x)=+x -(-x)=+x

Now let's write the exercise in the appropriate form:

0.43+0.87= -0.43+0.87=

We'll use the distributive property and solve the exercise step by step:

0.870.430.44 0.87\\-0.43\\0.44

Answer

0.44 0.44

Exercise #17

(+0.76)(+13.04)= ? (+0.76)-(+13.04)=\text{ ?}

Video Solution

Step-by-Step Solution

First we need to remember the rule:

(+x)=x -(+x)=-x

Now let's rewrite the exercise in the appropriate form:

0.7613.04= 0.76-13.04=

Next we will solve the exercise vertically, keeping in mind that the final result will be negative since we are subtracting a smaller number from a larger number:

13.040.7612.28 13.04\\-0.76\\12.28

Remember that the answer must be a negative number, so we will add a minus sign to get:

12.28 -\text{12}.28

Answer

12.28 -12.28

Exercise #18

(0.83)(14.68)= (-0.83)-(-14.68)=

Video Solution

Step-by-Step Solution

Let's remember the rule:

(x)=+x -(-x)=+x

Now let's write the exercise in the appropriate form:

0.83+14.68= -0.83+14.68=

We'll use the distributive property and solve the exercise step by step:

14.680.8313.85 14.68\\-0.83\\13.85

Answer

13.85 13.85

Exercise #19

(1214)(827)= (-12\frac{1}{4})-(-8\frac{2}{7})=

Video Solution

Step-by-Step Solution

Let's solve the problem step-by-step:

  • Step 1: Convert mixed numbers to improper fractions.

For 1214-12\frac{1}{4}, convert to an improper fraction:

1214=(12+14)=(484+14)=494-12\frac{1}{4} = -\left(12 + \frac{1}{4}\right) = -\left(\frac{48}{4} + \frac{1}{4}\right) = -\frac{49}{4}

For 827-8\frac{2}{7}, convert to an improper fraction:

827=(8+27)=(567+27)=587-8\frac{2}{7} = -\left(8 + \frac{2}{7}\right) = -\left(\frac{56}{7} + \frac{2}{7}\right) = -\frac{58}{7}

  • Step 2: Subtract the second improper fraction from the first.

The operation becomes 494(587)-\frac{49}{4} - (-\frac{58}{7}), which simplifies to 494+587-\frac{49}{4} + \frac{58}{7}.

Find a common denominator for 494\frac{49}{4} and 587\frac{58}{7}. The least common denominator is 28.

Convert 494-\frac{49}{4} and 587\frac{58}{7} to equivalents with a denominator of 28:

494=49×74×7=34328-\frac{49}{4} = -\frac{49 \times 7}{4 \times 7} = -\frac{343}{28}

587=58×47×4=23228\frac{58}{7} = \frac{58 \times 4}{7 \times 4} = \frac{232}{28}

So, 494+587-\frac{49}{4} + \frac{58}{7} becomes:

34328+23228=343+23228=11128-\frac{343}{28} + \frac{232}{28} = \frac{-343 + 232}{28} = \frac{-111}{28}

  • Step 3: Simplify the improper fraction 11128\frac{-111}{28} to a mixed number form.

Divide 111-111 by 28, which gives 3-3 and a remainder of 27. Thus:

32728-3\frac{27}{28}

Therefore, the solution to the problem is 32728-3\frac{27}{28}.

Answer

32728 -3\frac{27}{28}

Exercise #20

(1216)+(+1013)= (-12\frac{1}{6})+(+10\frac{1}{3})=

Video Solution

Step-by-Step Solution

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

  • Step 1: Convert the mixed numbers to improper fractions.
  • Step 2: Find a common denominator and add the fractions.
  • Step 3: Convert the resulting improper fraction back into a mixed number.

Let's begin by converting the mixed numbers into improper fractions:

The mixed number 1216 -12\frac{1}{6} can be converted as follows:

1216=(12×6+16)=736 -12\frac{1}{6} = -\left(\frac{12 \times 6 + 1}{6}\right) = -\frac{73}{6}

The mixed number +1013 +10\frac{1}{3} can be converted as follows:

1013=10×3+13=313 10\frac{1}{3} = \frac{10 \times 3 + 1}{3} = \frac{31}{3}

Next, we need a common denominator to add these fractions together. The denominators are 6 and 3, and the least common denominator is 6.

Convert 313\frac{31}{3} to have the denominator of 6:

313=31×23×2=626 \frac{31}{3} = \frac{31 \times 2}{3 \times 2} = \frac{62}{6}

Now, we add the fractions:

736+626=73+626=116 -\frac{73}{6} + \frac{62}{6} = \frac{-73 + 62}{6} = \frac{-11}{6}

Convert 116\frac{-11}{6} back into a mixed number:

116=156 \frac{-11}{6} = -1\frac{5}{6} (since 11÷6=1 11 \div 6 = 1 with a remainder of 5)

Therefore, the solution to the problem is 156 -1\frac{5}{6} .

Answer

156 -1\frac{5}{6}