Practice operations with decimal numbers with the exercises we have prepared. All exercises have answers explained step by step for you to clear your doubts.
question 1
Luzia went to the market to shop. She decided to check the statement issued by the cashier to check the items and prices, which marked the following values:
BRL 16.50
BRL 48.75
BRL 27.80
BRL 9.35
Determine the total amount paid by Luzia.
Answer: BRL 102.40.
question 2
A print shop is ordering shirts for an event. The customer placed an order for 60 white shirts with a print of the event's brand. The printing manager said that the unit cost of the shirt is R$23.50 and the printing service a fixed price of R$120.00, up to 100 shirts.
Determine the price per unit of printed shirt paid by the customer and the final price of the order.
Answer: BRL 1 530.00.
As there are 60 shirts at a cost of R$23.50 each, to obtain the cost of the shirts it is necessary to multiply them.
60 x 23.50 = 1,410.00
To determine the final amount that the customer paid, it is necessary to add the stamping service.
1 410,00 + 120,00 = 1 530, 00
question 3
Bruno, Cláudio, Daniel, Emerson and Fabrício make up the school's high school futsal team. In the last championship, each scored the following number of goals:
Bruno: 2
Claudio: 3
Daniel: 2
Emerson: 5
Fabricio: 4
Determine the average number of goals per player on the team in the last championship.
Answer: 3.2.
The average is the result of the sum of the values divided by the number of plots, in this case, five.
2 + 3 + 2 + 5 + 4 = 16
Since there are five players, we divide by five.
16 / 5 = 3,2
question 4
A clothing store is running a 20% off sale on all items. Joana wants to buy a blouse that costs R$49.90 and a pair of pants that cost R$79.90. How much will she pay for the two pieces with the discount?
Answer: BRL 103.84
To solve this problem, you need to multiply the price of each piece by 0.8, which is the discount factor.
Thus, we have:
Discount blouse price = 49.90 x 0.8 = 39.92
Price of discount pants = 79.90 x 0.8 = 63.92
Total discounted price = 39.92 + 63.92 = 103.84
Therefore, Joana will pay BRL 103.84 for the two pieces with the 20% discount.
question 5
A daily task is the payment and receipt of products and services. If payment is made in bills and coins, it is common to need change. Suppose a situation in which a payer delivers a R$50.00 bill to the receiver, for a R$23.20 product. Calculate the change needed.
Answer: R$26.80.
question 6
In a bakery, a chocolate pie was offered for sale. Customers ask for a piece that will have the mass measured, so they pay for what they consume. The whole pie weighs 1.6 kg and the total price is R$76.00. Suppose a customer has purchased a 100g piece. Determine the price the customer takes for his piece of pie.
Answer: BRL 4.75
We must think about which portion of the pie the customer's slice represents.
100 g = 0.1 kg
Thus, the slice represents 1/16 of the pie and to determine the price paid by the customer, we divide the total price by 16.
question 7
When purchasing a car, one of the factors that is usually taken into account is fuel consumption. This calculation is based on how many kilometers the car travels with one liter of fuel. Suppose a vehicle travels 11.5 km with one liter of fuel and has a tank with a capacity to store 50 liters.
In a certain situation, the fuel gauge informs that the tank has 1/3 of its capacity. Checking a route to be traveled, the driver identifies that there are 180 kilometers left to reach his destination. Make the calculations and determine if it is possible for the driver to complete the journey without the need for fuel stops.
If possible, determine how many kilometers you could still travel.
Answer: Yes, it would be possible and he could still travel about 10.9 km.
Calculation of the amount of current fuel in the tank.
Calculation of the estimate of how many kilometers the car can travel with this fuel.
Calculation of how many kilometers she could travel.
question 8
(CEDERJ 2018) Taking advantage of a “promotion”, Maria was able to buy a product for the fraction of its original price. The discount percentage was
2%
4%
6%
8%
To turn a fraction into a percentage, divide the numerator by the denominator.
23 / 25 = 0,92
After. we multiply by 100.
0.92 x 100 = 92%
We must determine which value was subtracted from 100% to get 92%.
Like this:
100 - 92 = 8
question 9
(UNESP 2011) A person needs 5 mg of vitamin E per week, to be obtained with the ingestion of two food supplements α and β. Each package of these supplements provides 1 mg and 0.25 mg of vitamin E respectively. This person has exactly BRL 47.00 per week to spend on the complements, with each α package costing BRL 5.00 and β BRL 4.00.
The minimum number of packets of the α food supplement that this person must ingest weekly, to guarantee the 5 mg of vitamin E at the fixed cost for the same period, is:
a) 3.
B)
c) 5.5.
d) .
e) 8.
The maximum number of packages a would be 5, because:
5 packages with 1 mg = 5 mg, costing 5 x R$5.00 = 25.00.
To decrease the amount of a and maintain the total of 5 mg in the week, we must increase the amount of b.
For 4 packets of a, we have 4 mg, and 1 mg needs to be added. Since each packet of b contains 0.25 mg, 4 packets of b are needed because:
0.25 x 4 = 1
4 packages a (4 mg a 4 x R$5.00 = R$20.00) + 4 packages b (1 mg a 4 x R$4.00 = R$16.00)
BRL 20.00 + BRL 16.00 = BRL 36.00
For 3 packets of a, we have 3 mg, making it necessary to top up 2 mg. Since each packet of b contains 0.25 mg, 8 packets of b are needed because:
0.25 x 8 = 2
3 packages a (3 mg at 3 x R$5.00 = R$15.00) + 8 packages b (2 mg at 8 x R$4.00 = R$32.00)
BRL 15.00 + BRL 32.00 = BRL 47.00
Thus, the minimum number of packages to keep supplementation within the R$47.00 budget is three packages.
question 10
(PUC-RJ 2018) The value of 0.5/0.05 + 0.05/0.005 is equal to:
a) 0.0005
b) 5
c) 10
d) 20
e) 25000
To solve this calculation it is more efficient to transform the decimal numbers into fractions.
Learn more with:
- division with comma
- Decimal Numbering System
- Exercises on decimal number system with answers
- Decimal numbers
ASTH, Rafael. Exercises on operations with decimal numbers.All Matter, [n.d.]. Available in: https://www.todamateria.com.br/exercicios-sobre-operacoes-com-numeros-decimais/. Access at:
See too
- Affine Function Exercises
- Fraction Exercises
- Percentage Exercises
- Combinatorial Analysis Exercises
- 27 Basic Mathematics exercises
- Inequality Exercises
- 1st Degree Equation - Exercises
- 6th grade math activities
