Division Review

Vicki Martinez

Divisibility Rules: Divisible by 2

If the last digit is even, the number is divisible by 2.

Example:

896 - ends in “6”. 6 is an even number. So 896 is divisible by 2.

29,765,433 - ends in “3”. 3 is an odd number. So this number is NOT divisible by 2.

Divisible by 3

If the sum of the digits is divisible by 3, the number is also .

Example: 345 (3 + 4 + 5 =12 and 12 ÷ 3 =4) That means that 345 is divisible by 3. 345 (3 + 4 + 6 =13 and 13 is not

divisible by 3). SO 345 is not divisible by 3.

Divisible by 5

If the last digit is a 5 or a 0, the number is divisible by 5.

Example: 155 This number ends in 5, so it is

divisible by 5. 150 This number ends in 0, so it is

divisible by 5 153 This number is not divisible by 5.

Divisible by 10

If the number ends in 0 , the number is divisible by 10.

Example: 340 ends in 0. It is divisible by

10.

343 does not end in 0. It is not divisible by 10.

Averaging – Finding the mean The mean is the average. Finding

the average means finding what is typical of the numbers in a set of data.

To find an average, add up all the numbers.

Count how many numbers you added. Divide the sum by the number of

numbers you added.

Example Find of the average of these numbers. 1. Add 2 + 2 + 8 + 8 +1 + 3 The total is: 24. How many numbers did we add? 6 2. Divide 24 ÷ 6 = 4

The average or mean of these numbers is 4.

Find the average of these numbers.

First add the numbers. 46 + 32 + 40 + 42 The sum is 160 Now divide that amount by 4

(because we added 4 numbers.) 160 ÷ 4=40 40 is the average.

The steps in division are:

Estimate and divide Multiply Subtract Bring Down Start over

Long Division Lesson

http://www.coolmath4kids.com/long-division/long-division-lesson-1.html

Practice with this site:

http://www.dositey.com/muldiv/divml1.htm