Practice the problems of Math in Focus Grade 4 Workbook Answer Key Chapter 8 Adding and Subtracting Decimals to score better marks in the exam.

## Math in Focus Grade 4 Chapter 8 Answer Key Adding and Subtracting Decimals

**Put On Your Thinking Cap!**

**Challenging Practice**

Question 1.

Miguel subtracts two numbers and gets the answer 4.95. The lesser of the two numbers is 3.4. What is the other number?

Answer:

The other number = 8.35.

Explanation:

Miguel subtracts two numbers and gets the answer 4.95.

Let the two number s be X and Y.

=> X – Y = 4.95.

The lesser of the two numbers is 3.4.

=> X – 3.4 = 4.95

=> X = 4.95 + 3.4

=> X = 8.35.

Question 2.

Julia subtracts two numbers and gets the answer 6.8. The greater of the two numbers is 10.55. What is the other number?

Answer:

The other number = 3.75.

Explanation:

Julia subtracts two numbers and gets the answer 6.8.

Let the two number s be X and Y.

=> X – Y = 6.8.

The greater of the two numbers is 10.55.

=> 10.55 – Y = 6.8

=> 10.55 = 6.8 + Y

=> 10.55 – 6.8 = Y

=> 3.75 = Y

**Put On Your Thinking Cap!
**

**Problem Solving**

Question 1.

The number in each rectangle is the sum of the numbers in the two circles next to it. Find the numbers in the circles.

Answer:

A = 0.3.

B = 1.1

C = 0.6

Explanation:

The number in each rectangle is the sum of the numbers in the two circles next to it.

=> Equation 1: A + B = 1.4

=> Equation 2: A + C = 0.9

=> Equation 3: B + C = 1.7.

Equation 1 – Equation 2

=> (A + B) – (A + C ) = 1.4 – 0.9

=> A + B – A – C = 0.5

=> B – C = 0.5.

=> B = 0.5 + C.

Equation 3 – Equation 2:

(B + C) – (A + C ) = 1.7 – 0.9

=> B + C – A – C = 0.8

=> B – A = 0.8.

=> A = B – 0.8.

Substitute A and B in Equation:1.

=> A + B = 1.4

=> B – 0.8 + B = 1.4

=> 2B – 0.8 = 1.4

=> 2B = 1.4 + 0.8

=> 2B = 2.2

=> B = 2.2 ÷ 2

=> B = 1.1.

A = 1.1 – 0.8

=> A = 0.3.

Substitute A = 0.3 in Equation 2:

=> A + C = 0.9

=> 0.3 + C = 0.9

=> C = 0.9 – 0.3

=> C = 0.6.

Question 2.

Each week, Rena saves $5. Her brother saves $2.50 less each week, but he started saving 4 weeks earlier. After how many weeks will Rena’s savings be equal to her brother’s?

Answer:

Number of weeks Rena’s savings be equal to her brother’s = 2.

Explanation:

Amount of money Rena saves each week = $5.

Her brother saves $2.50 less each week, but he started saving 4 weeks earlier.

Amount of money her brother saves each week = Amount of money Rena saves each week – $2.50.

= $5 – $2.50

= $2.50.

Total amount of money her brother saves for 4 weeks = 4 × Amount of money her brother saves each week

= 4 × $2.50

= $10.

Number of weeks Rena’s savings be equal to her brother’s = Total amount of money her brother saves for 4 weeks ÷ Amount of money Rena saves each week

= $10 ÷ $5

= 2.