Practice exercises on the decimal number system, used to perform calculations and represent quantities.
This is the numbering system most used in our daily lives. Its digits are: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. With its positional system of orders, we can write any number.
Check your answers with the feedback and take the opportunity to ask questions with the resolutions explained step by step.
Exercise 1
The decimal number system is positional, which means that the same digit represents different quantities depending on its position in the number.
Based on the number 65 872, how many tens are represented by the digit 5?
Answer: 500 tens.
The digit 5 is in the fourth order of thousands. At number 65,872 he is the first of the thousands class, representing 5,000 units, or, five thousand units.
To determine how many tens equals, simply divide by 10.
Exercise 2
With the numbers 7, 9, 0, 5 and 3, without repeating them and without using zero in the highest order position, write the largest and smallest possible number.
Minor: 30 579
Major: 97 530
The number has five orders, the largest being tens of thousands. To write the smallest number without zero being in the fifth order, we must use the next smallest, in this case, 3. Then proceed in ascending order.
30 579 (Thirty thousand five hundred and seventy nine)
To write the largest, we do the opposite, we start with the largest digit and continue in descending order.
97 530 (Ninety-seven thousand five hundred and thirty)
Exercise 3
In some documents such as receipts or checks, it is common that in addition to the number written in numbers, it is also written in full. Consider the following sales and purchase receipt:
Property purchase and sale receipt
Seller: Joao Fernandes
Buyer: Lucia de Castro
This receipt serves as proof of sale of the property. The seller declares that the property is free of encumbrances and charges, and the buyer assumes all responsibility for it from this date.
Sale value: BRL 356 765.00 _________________________________________________________________
Write in full as you would to fill out the receipt.
Answer: Three hundred and fifty-six thousand, seven hundred and sixty-five reais.
Exercise 4
Decompose the numbers in the form of a sum, representing each digit with its value in units.
a) 8 654 234
b) 516 325 974
a) 8 000 000 + 600 000 + 50 000 + 4 000 + 200 + 30 + 4
b) 500 000 000 + 10 000 000 + 300 000 + 20 000 + 5 000 + 900 + 70 + 4
Exercise 5
Write the place value of the digit 7 in each case.
a) 756 000
b) 9 654 327
c) 50 071
d) 57 501 000
a) Seven hundred thousand.
b) Seven simple units.
c) Seven simple tens.
d) Seven units of a million.
Exercise 6
Carefully read the following text:
The company's expansion project foresees an investment of around 2.5 billion reais in the coming years. The forecast is that this investment will bring an increase of at least 500 million reais in the company's annual revenue. With this growth, the company is expected to surpass the mark of 4.67 billion reais in revenue by the end of the decade.
Use figures to represent the numbers cited in the text, with monetary indication.
2.5 billion reais = BRL 2 500 000 000.00
500 million reais = BRL 500 000 000.00
4.67 billion reais = BRL 4,670,000,000.00
Exercise 7
Write the number formed by the following indications using numbers, then spell it out in full.
Eight billion ones, five tens of millions, nine hundred thousand, one thousand, seven tens and three ones.
Response:
8 050 901 073: eight billion fifty million nine hundred and one thousand seventy-three.
Exercise 8
(Enem 2022) Upon hearing the news that a newly released film grossed BRL 1.35 in the first month of release billion at the box office, a student correctly wrote the number representing that amount, with all its digits.
The number written by the student was
a) 135,000.00
b) 1,350,000.00
c) 13 500 000.00
d) 135 000 000.00
e) 1 350 000 000.00
The digit 1 before the decimal point represents the integer part, in this case, 1 billion. Filling in the other classes and orders, we have:
1 350 000 000,00
Exercise 9
(IDHTEC - 2016) Our decimal numbering system is so called because:
a) It is formed by numbers with a comma.
b) Does not allow leaks to other systems.
c) It has only 9 digits for the formation of numbers.
d) It has 10 digits for the formation of numbers and each position has a meaning.
e) It has all possible fractions.
The symbols used, called digits, are: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Depending on the position in which it occupies, it has a certain value. These positions are called orders.
Exercise 10
(Army - Military College - 2015) The symbols
represent three of the ten digits used in the decimal numbering system. Note the addition of five natural numbers below.
Knowing that equal symbols represent equal digits and, considering the previous situation, what is the value of the addition illustrated below?
a) 95
b) 109
c) 545
d) 901
e) 4,505
We must analyze: what number added five times equals 545? This is equivalent to determining the number that multiplied by five equals 545.
To determine the number we do the division operation.
In this way, we identify that:
smile = 1
star = 0
heart = 9
In the second indication, the number multiplied by five is, in this order, formed by:
heart, star, smile = 901
Therefore,
To learn more, see:
- Decomposing numbers in the decimal number system
- What are Decimal Numbers?
- Operations with decimal numbers
ASTH, Rafael. Exercises on decimal number system with answers.All Matter, [n.d.]. Available in: https://www.todamateria.com.br/exercicios-sobre-sistema-de-numeracao-decimal-com-respostas/. Access at:
See too
- Operations with decimal numbers
- Decimal Numbering System
- Decimal numbers
- Decomposing numbers in the decimal number system
- Exercises on Rational Numbers
- 6th grade math activities
- 27 Basic Mathematics exercises
- Rational Numbers
