What is Divisor?

The number we are dividing by.

A divisor is the number that tells us how many equal parts we are splitting something into. It’s what we use to divide the total (called the dividend).

At Mathnasium, we explain division as “How many of these are inside of that?” The divisor is the “these.” It’s the size of the group or the number of parts you want.

Here’s how to spot it:

In 12 ÷ 4 = 3, the 4 is the divisor.
In a ÷ b = c, the b is the divisor.
In fraction form \(\frac{a}{b}\) = c , the denominator (b) is also the divisor.

Components of division: dividend, divisor, quotient

Let’s explore more examples:

20 ÷ 5 where 5 is the divisor
36 / 6 or \(\frac{36}{6}\) where 6 is the divisor (and a denominator)
In long division, if you’re dividing 36 by 6, the 6 is placed outside the division bracket and is the divisor.

The divisor helps us figure out either how many parts something is split into, or how many times it fits into the dividend.

When Do Students Learn About Divisors?

Most students begin working with divisors when they first learn about division, even if they don’t know the term yet. The formal vocabulary usually comes in a little later, as their understanding deepens.

Grades 2–3 – Division Basics

Students use objects and visual models to divide things into equal groups. They explore the concept of dividing by a number before being introduced to the term “divisor.”