Table of Contents
What are the Divisibility Rules?
Divisibility Rules:
There are five divisibility rules, which are as follows:
The number is divisible by 2 if the last digit is even.
The number is divisible by 3 if the sum of the digits is divisible by 3.
The number is divisible by 5 if the last digit is a 5 or a 0.
The number is divisible by 10 if the last digit is a 0.
The number is divisible by both 2 and 3 if the number is divisible by both 2 and 3.
Importance of Factors
There are several important factors to consider when making a decision. The most important factors will vary depending on the situation. Some of the most important factors in decision making are:
- The potential consequences of the decision
- The available information
- The time available to make the decision
- The available resources
- The possible risks and rewards associated with the decision
Just Like Fractions
Just like fractions, proportions can be written as a number over another number. For example, if there are ten students in a classroom and twenty desks, the proportion of students to desks is 10:20, or 1:2. This means that for every one student there are two desks.
Long Division Method
- To divide a number by a single digit number, use the long division method.
- To divide a number by a two digit number, use the long division method.
- To divide a number by a three digit number, use the long division method.
How to Write it Down?
When writing out the problem, it is important to be specific and concise. It is also helpful to use diagrams or pictures to illustrate the problem. For example, if the problem is algebra-based, it might be helpful to draw a picture of the equation.
A Few Tips for Long Division
-Remember your multiplication tables
-Make sure you are using the correct division algorithm (long division, short division, or divisibility rules)
-Draw a picture or use a number line to help you understand the problem
-Check your work!
Divisibility Tests
- A number is divisible by 2 if the last digit is even.
- A number is divisible by 3 if the sum of the digits is divisible by 3.
- A number is divisible by 5 if the last digit is a 5 or a 0.
- A number is divisible by 9 if the sum of the digits is divisible by 9.
Divisibility Rules for the Numbers 2–11
- The divisibility rule for 2 is that the number is divisible by 2 if the last digit is even.
- The divisibility rule for 3 is that the number is divisible by 3 if the sum of the digits is divisible by 3.
- The divisibility rule for 5 is that the number is divisible by 5 if the last digit is 0 or 5.
- The divisibility rule for 7 is that the number is divisible by 7 if the sum of the digits is divisible by 7.
- The divisibility rule for 9 is that the number is divisible by 9 if the sum of the digits is divisible by 9.
- The divisibility rule for 11 is that the number is divisible by 11 if the sum of the digits is divisible by 11.
