Quantitative Aptitude

Number System and Digits

374 Questions

Number system and digits questions test the ability to manipulate numbers, identify significant digits, and form specific values. These problems often require finding missing digits or determining the properties of large sums. They form a vital component of the quantitative aptitude section.

Number formationMissing digitsSignificant digitsLargest and smallest numbersDigit sum properties

Number System and Digits Questions

Multiple choice

In a number system, 11 is equivalent to 6 of decimal number system. What is the base of the number system of 11?

  1. 2

  2. 10

  3. 6

  4. 5

  5. 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The positional weight of digits in a number in a number system with base n are given by 1, n, n2 ....... etc. starting from rightmost place moving one place leftward. So, 11 = n + 1 in decimal system where n is the base of the number system of 11. Thus, n + 1 = 6 as per the question. Hence, n = 5

Multiple choice

A 4 digit hexadecimal number is converted to binary number system. The leftmost digits are ignored. Which of the following is not possible?

  1. The binary equivalent of the 4 digit hexadecimal number has 13 digits.

  2. The binary equivalent of the 4 digit hexadecimal number has 14 digits.

  3. The binary equivalent of the 4 digit hexadecimal number has 15 digits.

  4. The binary equivalent of the 4 digit hexadecimal number has 16 digits.

  5. The binary equivalent of the 4 digit hexadecimal number has 17 digits.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

While converting a hexadecimal number to binary, we can convert each digit to a 4 digit binary number and write them in order of the hexadecimal digits. Thus, the resulting binary number will be of 16 digits. If the leftmost hexadecimal digit is less than 8, we will have zeroes on the left in the binary equivalent of such numbers. In any case the number of digits will not be more than 16.

Multiple choice

Which two digits are used in the binary number system?

  1. 1 and 2

  2. 0 and 1

  3. 1 and 10

  4. 5 and 10
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The binary number system uses only two digits: 0 and 1. This base-2 system is fundamental to digital computing because it represents the two states of electronic switches (on/off).

Multiple choice

Binary system is the numbering system that uses only ___ digit(s).

  1. 1

  2. 2

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The binary number system uses exactly 2 digits: 0 and 1. This is fundamental to digital computing because electronic circuits can easily represent two states (on/off or true/false). The prefix 'bi' means two, as in bicycle (two wheels) or bilingual (two languages). Option B is correct.