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Divisibility Rules. 7 Math Section 3-3. Divisibility Rules: What are they?. Rules to help you determine if numbers are divisible by other numbers. Divisible – if a number can be divided by another number with no remainder, decimal, or fraction.
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Divisibility Rules • 7 Math • Section 3-3
Divisibility Rules: What are they? • Rules to help you determine if numbers are divisible by other numbers. • Divisible – if a number can be divided by another number with no remainder, decimal, or fraction. • We will learn rules for 2, 3, 4, 5, 6, 8, 9, and 10.
Divisibility Rule for 2 • A number is divisible by 2 if… • The number is even. • Even numbers end in 2, 4, 6, 8, or 0. • Examples • 412 • 230 • 516
Divisibility Rule for 10 • A number is divisible by 10 if… • The number ends in a zero. • Examples • 4,000 • 210 • 50
Divisibility Rule for 5 • A number is divisible by 5 if… • The number ends in a 5 or 0. • Examples • 4,000 • 215 • 355
Divisibility Rule for 3 • A number is divisible by 3 if… • The sum of the digits of the number is divisible by 3. • Examples • 354 • 3 + 5 + 4 = 12 • 12 / 3 = 4 • 9,363,129 • 9 + 3 + 6 + 3 + 1 + 2 + 9 = 33 • 33/3 = 11
Divisibility Rule for 9 • A number is divisible by 9 if… • The sum of the digits of the number is divisible by 9. • Examples • 495 • 4 + 9 + 5 = 18 • 18 / 9 = 2 • 999,918 • 9 + 9 + 9 + 9 + 1 + 8 = 45 • 45 / 9 = 5
Divisibility Rule for 6 • A number is divisible by 6 if… • The number is divisible by both 3 and 2. • Examples • 930 • 6000 • 216
Divisibility Rule for 4 • A number is divisible by 4 if… • The last 2 digits of the number is divisible by 4. • Examples • 9,264 • 1,209,124 • 216
Divisibility Rule for 8 • A number is divisible by 8 if… • The last 3 digits of the number are divisible by 8. • Examples • 9,808 • 8,942,216 • 848
Divisibility Rules • A number is divisible by: • 2 if the number is even. • 3 if the sum of the digits is divisible by 3. • 4 if the last 2 digits of the number are ÷ by 4. • 5 if the number ends in a 5 or 0. • 6 if the number is divisible by 2 and 3. • 8 if the last 3 digits of the number are ÷ by 8. • 9 if the sum of the digits is divisible by 9. • 10 if the number ends in a 0.
What number(s) is the number below divisible by? • 27 • 3 and 9
What number(s) is the number below divisible by? • 42 • 2, 3, 6
What number(s) is the number below divisible by? • 2,848 • 2, 4, and 8
What number(s) is the number below divisible by? • 9,990 • 2, 3, 5, 6, 9, and 10
What number(s) is the number below divisible by? • 17 • None
Homework • Pages 143-144 • (2-40 evens) 18