Examples with solutions for Addition, Subtraction, Multiplication and Division: Decimal numbers

Exercise #1

7(5)+8.5+(13)=? -7-(-5)+8.5+(-13)=\text{?}

Video Solution

Step-by-Step Solution

Let's begin by expanding the parentheses. Make sure to pay attention to the minus and plus signs, which change accordingly:

(5)=5 -(-5)=5

8.5+(13)=8.513 8.5+(-13)=8.5-13

We should obtain the following:

7+5+8.513= -7+5+8.5-13=

Now let's solve the exercise from left to right:

2+8.513= -2+8.5-13=

6.513=6.5 6.5-13=-6.5

Answer

6.5 -6.5

Exercise #2

7.5+(9.5)+5+(13.5)=? 7.5+(-9.5)+5+(-13.5)=\text{?}

Video Solution

Step-by-Step Solution

Let's begin by expanding the parentheses whilst paying attention to the minus and plus signs, which change accordingly:

+(9.5)=9.5 +(-9.5)=-9.5

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

We should obtain the following:

7.59.5+513.5= 7.5-9.5+5-13.5=

Now let's solve the exercise from left to right:

2+513.5= -2+5-13.5=

313.5=10.5 3-13.5=-10.5

Answer

10.5 -10.5

Exercise #3

3.5×4+16×2.5=? 3.5\times4+16\times2.5=\text{?}

Video Solution

Step-by-Step Solution

According to the order of operations rules, we must first solve the multiplication exercises and then add them together:

(3.5×4)+(16×2.5)= (3.5\times4)+(16\times2.5)=

14+40=54 14+40=54

Answer

54 54

Exercise #4

4.5+12.5+10.513.5=? 4.5+12.5+10.5-13.5=\text{?}

Video Solution

Step-by-Step Solution

Let's solve the exercise from left to right since we are only dealing with addition and subtraction operations:

4.5+12.5=17 4.5+12.5=17

17+10.5=27.5 17+10.5=27.5

27.513.5=14 27.5-13.5=14

Answer

14 14