# Aptitude Number System

**Number system** is a important chapter of aptitude.

To make a good score in aptitude section of competitive exam, interview you must have a good mark in number system.

Number system question is divided into six module :

- Factors
- Highest Power
- Ending With Zero
- Remainder
- Unit place
- Divisibility

All the six module are describe with example.

## Important Formula of Factor

To find the **number of factor** for a given number

N= a^{p}+b^{q}+c^{r}

Is given by

Number of factor (NF)=(p+1)*(q+1)*(r+1)

To find the number of **even factor** for a given number

N= a^{p}*b^{q}*c^{r}

Is given by

NF Even=(p)*(q+1)*(r+1)

To find the number of **odd factor** for a given number

NF Odd=Number of factor-Number of ever factor