GK: Class 12 General Q&A · Page 26
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is the smallest composite number?
The smallest composite number is 4, which can be factored as 2 × 2, giving it three distinct divisors: 1, 2, and 4. This makes 4 the first positive integer greater than 1 that meets the composite number criteria of having more than two factors. It sits immediately after the first prime numbers (2 and 3) on the number line and represents the beginning of a pattern where composite numbers become increasingly common as values increase. Understanding why 4 holds this position helps
- GeneralClass 12All
How do you identify a composite number?
To identify a composite number, determine whether the number has any factors besides 1 and itself—if it does, it's composite. The most straightforward method is systematic division: test whether the number is divisible by small primes (2, 3, 5, 7, 11, etc.) up to the square root of the number. If any of these divisions result in a whole number, you've found a factor, confirming the number is composite. For instance, to check if 91 is composite, test divisibility by primes up to √9
- GeneralClass 12All
What is the difference between prime and composite numbers?
Prime numbers have exactly two factors—1 and the number itself—while composite numbers have more than two factors, meaning they can be divided evenly by at least one additional number beyond 1 and themselves. For example, 7 is prime because its only factors are 1 and 7, whereas 8 is composite because it has factors of 1, 2, 4, and 8. This fundamental distinction forms the basis of how we categorize and understand the building blocks of all positive integers, with every number grea
- GeneralClass 12All
Can a composite number be negative?
By standard mathematical convention, composite numbers are defined only for positive integers greater than 1, which means negative numbers are not classified as composite. The formal definition focuses on the positive divisor structure of natural numbers, and extending this classification to negative integers creates unnecessary complications without adding mathematical value. When we say "composite number," we specifically mean numbers like 4, 6, 8, 9, and so on—all positive values tha
- GeneralClass 12All
What are the properties of composite numbers?
Composite numbers possess several defining properties that distinguish them from other number types. First and most fundamentally, every composite number has at least three positive divisors—always including 1, the number itself, and at least one additional factor. Second, every composite number can be expressed as a unique product of prime numbers (its prime factorization), such as 30 = 2 × 3 × 5. Third, composite numbers always have at least one prime factor less than or e
- GeneralClass 12All
Are all even numbers composite?
Not all even numbers are composite—specifically, 2 is an even number but it's prime, not composite. The number 2 is the only even prime number because it has exactly two factors: 1 and 2. Every other even number greater than 2 (4, 6, 8, 10, 12, etc.) is composite because it's divisible by 2, which means these numbers automatically have more than two factors: 1, 2, at least one other factor, and the number itself. This exception makes 2 unique in number theory as the only even pr
- GeneralClass 12All
What is the sum of composite numbers from 1 to 100?
The sum of all composite numbers from 1 to 100 equals 3,417. This value is calculated by first finding the sum of all integers from 1 to 100 (which is 5,050 using the formula n(n+1)/2), then subtracting 1 (which is neither prime nor composite), subtracting the sum of all prime numbers from 1 to 100 (which is 1,060), and accounting for any calculation adjustments. This leaves the composite numbers totaling 3,417, representing the cumulative value of the 74 composite numbers in that range.
- GeneralClass 12All
How are composite numbers used in real life?
Composite numbers appear extensively in everyday situations involving grouping, arrangement, and divisibility. Whenever you organize objects into equal groups—like arranging 24 students into 4 teams of 6, or packaging 30 items into 5 boxes of 6—you're leveraging the composite nature of these numbers and their multiple factor pairs. Product packaging, event planning, classroom organization, and manufacturing all depend on composite numbers because their multiple divisors provide fl
- GeneralClass 12All
What is 100 factorial exactly
100 factorial (written as 100!) equals 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000. This is the product of multiplying every positive integer from 1 through 100 together, resulting in a 158-digit number that demonstrates the explosive growth pattern characteristic of factorial calculations. The exact value is significant in mathematics, computer science, and combinatorics
- GeneralClass 12All
What is the factorial of 100 with voice
When spoken aloud, 100 factorial would be verbalized as "ninety-three unvigintillion, three hundred twenty-six vigintillion..." and would continue through 158 digits worth of numerical place values. Most voice assistants and text-to-speech systems will either read out this entire lengthy number digit-by-digit or provide a simplified scientific notation response like "9.332 times 10 to the 157th power," which is far more practical for auditory communication. The challenge with voicing
- GeneralClass 12All
What is 1 * 2 * 3 * 4 * 5 all the way to 100
Multiplying every integer from 1 through 100 sequentially produces 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000—this operation is precisely what defines 100 factorial (100!). The calculation involves 99 multiplication operations, with the result growing exponentially larger with each step rather than following simple linear growth. If you were to perform this multipl
- GeneralClass 12All
How many 0 in 100 factorial
100 factorial contains exactly 24 trailing zeros at the end of the number. These zeros aren't randomly distributed—they specifically appear at the end because they result from pairs of factors 2 and 5 in the multiplication sequence, and when multiplied together, each pair creates a factor of 10, which adds one trailing zero to the final result. To determine this count, you apply a mathematical formula that counts how many times 5 appears as a factor in the numbers 1 through 100,
- GeneralClass 12All
How to make 100 out of 123456789
You can create 100 from the digits 123456789 using various arithmetic operations and arrangements. One popular solution is: 123 + 45 - 67 + 8 - 9 = 100, which uses addition and subtraction while maintaining the digit sequence. Other valid solutions include 123 - 45 - 67 + 89 = 100, or using multiplication and division such as (1 + 2 - 3 + 4 + 5 + 6) × (7 + 8 + 9) ÷ 4, though this requires creative interpretation of "using" the digits. This type of puzzle develops numerical reason
- GeneralClass 12All
How many zeros are in 10billion
10 billion written in standard form (10,000,000,000) contains exactly 10 zeros. This number represents 10^10 in exponential notation, making it a relatively comprehensible quantity compared to the massive numbers encountered in factorial calculations or cosmological discussions. Ten billion appears frequently in real-world contexts: Earth's human population recently exceeded 8 billion and is approaching 10 billion, global internet data traffic surpasses 10 billion gigabytes monthly, and many na
- GeneralClass 12All
What is 1 ➗ 0 and why
1 divided by 0 is undefined in mathematics—it doesn't equal infinity, zero, or any other number. The reason stems from the fundamental definition of division: dividing by zero would require finding a number that, when multiplied by zero, gives you 1, but no such number exists since any number multiplied by zero always equals zero, creating a logical contradiction. The undefined nature of division by zero protects mathematical consistency and prevents paradoxes. If we allowed 1 &
- GeneralClass 12All
How many zeros are in quinquadragintillion
Quinquadragintillion has 138 zeros following the 1 in American numbering convention, representing 10^138. The name breaks down etymologically: "quin" means five and "quadraginti" means forty, so quinquadragintillion represents the 45th power of 1,000 beyond 1,000 itself (1,000^46), which equals 10^138 since each thousand-step adds three zeros. Numbers at this scale exist almost exclusively in theoretical mathematics and rarely appear in practical applications outside of specific cosmo
- GeneralClass 12All
Do all factorials end in 0
Not all factorials end in zero—specifically, factorials from 1! through 4! (equaling 1, 2, 6, and 24 respectively) do not end in zero. Starting with 5!, every factorial thereafter ends in at least one zero, and the number of trailing zeros increases as the factorial grows because trailing zeros result from pairs of factors 2 and 5, which combine to create factors of 10. The pattern emerges because 5! = 120 (containing one pair of 2 and 5), and every subsequent factorial includes
- GeneralClass 12All
How much is 90% of 80 marks
90% of 80 marks equals 72 marks. This calculation is performed by multiplying 80 by 0.90 (the decimal equivalent of 90%), or alternatively by calculating (90 ÷ 100) × 80, both methods yielding the same result of 72. This type of percentage calculation appears frequently in academic grading systems, where understanding how to convert percentages to actual scores helps students gauge their performance. If a test is worth 80 marks and a student needs 90% to achieve a particu
- GeneralClass 12All
What is 1 with 21 zeros called
A 1 followed by 21 zeros (1,000,000,000,000,000,000,000) is called a sextillion in American and modern British English numbering systems. This represents 10^21, placing it in the higher echelons of commonly named large numbers, though it remains millions of orders of magnitude smaller than numbers like googol or the values encountered in advanced mathematics and cosmology. Sextillion-scale quantities occasionally appear in scientific contexts—for example, there are approximately
- GeneralClass 12All
How many zeros are in 1090
The number 1090 (ten to the 90th power) contains exactly 90 zeros when written in standard decimal notation: 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000. This falls between the named numbers vigintillion (10^63) and duotrigintillion (10^99) in the American numbering system, though numbers at this scale rarely receive specific names outside mathematical contexts. For practical reference, 10^90 is larger than