Introduction

Numbers can be categorised into types based on the number of factors obtained in factorization. They are prime numbers and composite numbers. A number with only two factors, one and the number itself, is a prime number. A composite number has more than two factors, therefore it can be divided by at least one positive integer in addition to the by 1 and number itself.

Explanation

The following is a list of composite numbers between 1 to 100:

\mathrm{4},\mathrm{6},\mathrm{8},\mathrm{9},\mathrm{10},\mathrm{12},\mathrm{14},\mathrm{15},\mathrm{16},\mathrm{18},\mathrm{20}

\mathrm{21},\mathrm{22},\mathrm{24},\mathrm{25},\mathrm{26},\mathrm{27},\mathrm{28},\mathrm{30},\mathrm{32},\mathrm{33},\mathrm{34}

\mathrm{35},\mathrm{36},\mathrm{38},\mathrm{39},\mathrm{40},\mathrm{42},\mathrm{44},\mathrm{45},\mathrm{46},\mathrm{48},\mathrm{49}

\mathrm{50},\mathrm{51},\mathrm{52},\mathrm{54},\mathrm{55},\mathrm{56},\mathrm{57},\mathrm{58},\mathrm{60},\mathrm{62},\mathrm{63}

\mathrm{64},\mathrm{65},\mathrm{66},\mathrm{68},\mathrm{69},\mathrm{70},\mathrm{72},\mathrm{74},\mathrm{75},\mathrm{76},\mathrm{77}

\mathrm{78},\mathrm{80},\mathrm{81},\mathrm{82},\mathrm{84},\mathrm{85},\mathrm{86},\mathrm{87},\mathrm{88},\mathrm{90},\mathrm{91}

\mathrm{92},\mathrm{93},\mathrm{94},\mathrm{95},\mathrm{96},\mathrm{98},\mathrm{99},\mathrm{100}

On counting, we can find that there are 74 composite numbers between 1 and 100.

Conclusions

There are three distinct methods that can be used to find the composite numbers.

• Prime Number Method: This is the simplest technique because all other numbers are composite, thus all you need to know are the prime numbers. We also need to remember that 1 is neither prime nor composite.

• Factorisation Method: To determine whether a number is composite or not, you must identify its prime factors. The number is composite if it has more than two prime factors.

• Divisibility Method: You must check that the provided number is divisible by using this method. It is composite if there are more than two divisors.

Using any of the three above said methods one can find that there are seventy-four composite numbers in total between one to hundred.

As we can observe from above, there are in total 74 composite numbers between 1 and 100.