ADDING AND SUBTRACTING DECIMALS

Find :

Problem 1 :

Solution :

Add :

Problem 2 :

a) 38.76, 132.8 and 9.072

b) 18.61, 236.9 and 1072.4

Solution :

Find :

Problem 3 :

Solution :

Subtract :

Problem 4 :

a)  8.615 from 19.837

b)  14.86 from 28.79

Solution :

Problem 5 :

A 20 m length of rope is cut into 4 pieces. Three of the pieces have lengths 5.62 m, 8.05 m, and 2.6 m. Find the Length of the fourth pieces.

Solution :

Given,

The length of the rope is 20 m and it is cut into four pieces.

Length of first piece = 5.62 m

Length of second piece = 8.05 m

Length of third piece = 2.6 m

Let the length of the fourth piece be x.

Length of rope = Sum of the length of four pieces

20 = 5.62 + 8.05 + 2.6 + x

20 = 16.27 + x

20 - 16.27 = x

3.73 = x

So, the length of the fourth piece is 3.73 m.

Problem 6 :

A weightlifter snatches 135.8 kg, 142.9 kg, and 153.7 kg in consecutive lifts. Find the total mass lifted.

Solution :

Total lifted weight = Sum of his each consecutive lifted weights

= 135.8 + 142.9 + 153.7

= 432.4 kg

Problem 7 :

A large envelope contains only $5 bills. The total value of the $5 bills is $2,435. Which equation can be used to find the number of $5 bills in the envelope?

a) 2,435 ÷ 5 = 487      b) 2,435 × 5 = 12,175     c) 2,435 + 5 = 2,440

d)  2,435 - 5 = 2,430

Solution :

Here the number of $5 bill is unknown

Total value of $5 bill is $2435

Value of each bill = $5

Total value / value of each bill = number of bills

2,435 ÷ 5 = 487

Problem 8 :

Ms. Lanford buys and sells used clothes. Ms. Lanford bought a dress, a sweater, and shorts for a total of $12.00. She then sold each item for the price shown in the list.

• She sold the dress for $20.75.

• She sold the sweater for $15.25.

• She sold the shorts for $8.50.

What was Ms. Lanford’s total profit from selling the dress, sweater, and shorts?

a)  $12.00      b)  $56.50     c)  $32.50       d)  $44.50

Solution :

Selling price of all itemns = 20.75 + 15.25 + 8.50

= 44.5

Total value of all items = 12

Profit = Selling price - cost price

= 44.5 - 12

= 32.50

So, option c is correct.

Problem 9 :

Lindsey purchased one pet carrier that cost $21.89 and 2 bags of cat food that cost $16.49 each. What was the total cost of these items?

a) $54.87      b) $38.38      c) $43.67      d) $32.98

Solution :

Cost of pet carrier = 21.89

Cost of cat food  = 16.49 each

Total cost = 2(16.49) + 21.89

= 32.98 + 21.89

= 54.87

So, option a is correct.

Problem 10 :

Della wrote a number:

• The digit in the hundredths place is a 4.
• The digit in the thousands place is a 7.
• The digit in the tenths place is a 2.

Which number could be the number Della wrote?

a) 537,106.24      b) 17,420      c) 27,389.04      d) 70.24

Solution :

Option a :

537,106.24

• Number is at the tenths place = 2
• Number is at the hundredths place = 4
• Number is at thousands place = 7

So, option a is correct.

Problem 11 :

At the beginning of the month, Jim's bank balance was $275.38. During the month he wrote the following checks: $174.89, $68, and $57.76. He made deposits of $250 and $350. Find his bank balance at the end of the month.

Solution :

Jim's bank baalnce = 275.39

After writing checks, the remaining amount he will have 

= 275.39 - (174.89 + 68 + 57.76)

= 275.39 - 300.65

= -25.26

He is making deposits for the amounts $250 and $350

= -25.26 + 250 + 350

= 574.74

So, the bank balance at the end of the month is $574.74

Problem 12 :

Rudy drove his car 9,600 miles last year. His total car expenses were $625 for the year. Find the average cost per mile. (Round off your answer to the nearest hundredth)

Solution :

Distance covered = 9600 miles

Total expense = 625

Average cost = 625/9600

= 0.065

So, the average cost is 0.065 per mile.