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Grade 7:  The Learning Equation Math

11.04 Divisibility Rules

 Number Concepts Refresher pp 8-9
Learning Outcomes:

The student will:

Characteristic of number Number divisible by:
Last digit is even 2
The sum of the digits is divisible by 3 3
The last two digits form a number divisible by 4 4
The last digit is 0 or 5 5
The number is divisible by both 2 and 3. 6
To find out if a number is divisible by seven, take the last digit, double it, and subtract it from the rest of the number.

If you get an answer divisible by 7 (including zero), then the original number is divisible by seven. If you don't know the new number's divisibility, you can apply the rule again.

7

Example:  Check to see if 203 is divisible by 7.

• double the last digit: 3 x 2 = 6
• subtract that from the rest of the number: 20 - 6 = 14.
• check to see if the difference is divisible by 7: 14 is divisible by 7, therefore 203 is also divisible by 7.
The last three digits form a number divisible by 8 8
The sum of the digits is divisible by 9 9
The numeral ends in 0 10

The (sum of the odd numbered digits) - (sum of the even numbered digits) is divisible by 11.

Example:

34871903
3+8+1+0=12
4+7+9+3=23
23-12=11
Is divisible by 11

11
The number is divisible by both 3 and 4. 12
Delete the last digit from the number, then subtract 9 times the deleted digit from the remaining number. If what is left is divisible by 13, then so is the original number. 13
The last four digits form a number divisible by 16 16
TEST TIP:    If a number is divisible by two different prime numbers, then it is divisible by the products of those two numbers.  Since 36, is divisible by both 2 and 3, it is also divisible by 6.

Quia - Flashcards - Rules of Divisibility - flash cards

Review:

Lesson on Divisibility Tests

Enrichment:

Divisibility Rules

 Key Terms: A-E F-J K-O P-R S-Z

divisible, quotient, remainder, whole number, factor, multiple, even number, odd number, prime number, composite number

Prerequisite Skills:

Powers and Exponents:  Grade 7 Lesson 11.01

 Five in a Row Do you remember your tables of multiplication? This game is about the tables of multiplication from 1 to 10. A number is presented and you have to choose a multiplication that has this number as result. Was your choice correct? If so, then the box is colored and a new number is presented. Try to get five colored boxes in a row (on a diagonal is also possible). Click the following link to play the game: Five in a row

Multiplication Flashcards

Multiplication by One-Digit Numbers

Division of Decimals:  Grade 7 Lesson 12.02

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