Question

Which of the following numbers are prime?1011121314151617181920

Answer 1

`11,13,17,19`

Step-by-step explanation

Prime numbers are numbers that have only 2 factors: 1 and themselves.

then

`\begin{gathered} 10\text{ can be factorized as 5}\cdot2 \\ 11\text{ can not be factorized}\Rightarrow prime \\ 12\text{ can be factorized as 3}\cdot4 \\ 13\text{can not be factorized}\Rightarrow prime \\ 14\text{ can be factorized as 7}\cdot2 \\ 15\text{can be factorized as 3}\cdot5 \\ 16\text{can be factorized as 2}\cdot8 \\ 17\text{can not be factorized}\Rightarrow prime \\ 18\text{can be factorized as 2}\cdot9 \\ 19\text{can not be factorized}\Rightarrow prime \\ 20\text{ can be factorized as 10}\cdot2 \end{gathered}`

so, the prime numbers are

`11,13,17,19`

I hope this helps you