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1-5 Divisibility 9/14/09. Objective: use divisibility rules to solve division problems. Vocabulary. Dividend Number being divided Divisor Number dividing up the dividend Doing the dividing up Quotient The result of a division problem Divisible If the remainder is zero.
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1-5 Divisibility 9/14/09 Objective: use divisibility rules to solve division problems
Vocabulary • Dividend • Number being divided • Divisor • Number dividing up the dividend • Doing the dividing up • Quotient • The result of a division problem • Divisible • If the remainder is zero
Divisible by 5 • Multiple of 5 • Ends in 0 or 5 • Name three numbers that are divisible by 5 (at least three digits)
Divisible by 10 Ends in 0 Name three numbers that are divisible by 5 and 10 (at least three digits)
Divisible by 2 • Is the number even? • Meaning the number ends in 0, 2, 4, 6, 8 • Which of the following numbers are divisible by 2? • 2,001 • 422 • 97,734
Divisible by 3 • The sum of the digits is divisible by 3 • Add up all of the digits: 312 • 3 + 1 + 2 = 6 • Ask yourself if 3 goes into that number evenly • If the answer is yes, it is divisible by 3 • 6 / 3 = 2 • 312 is divisible by 3 • Which of the following numbers are divisible by 3? • 456 • 133
Divisible by 6 • If the number is divisible by 2 and 3 • Check if the number is even • Check if the sum of the digits is divisible by 3 • If the answer is yes to both questions, the number is divisible by 6 • 942 • Ends in 2, so it is even (divisible by 2) • 9 + 4 + 2 = 15 15/3 = 5 (divisible by 3) • Divisible by 6 because it passes the divisibility test for 2 and 3 • Is 1,234 divisible by 6? Prove it! • Ends in 4, so it is divisible by 2 • 1 + 2 + 3 + 4 = 10 (10 is not divisible by 3)
Divisible by 9 • The sum of the digits is divisible by 9 • What rule is this similar to? • Name three numbers that are divisible by 9 (each number must be at least three digits)
Divisible by 4 • The last two digits are divisible by 4 • 12,344 • 44/4 = 11 • 99,824 • 24/4 = 6 • Name two four-digit numbers that are divisible by 4
Let’s Test the Divisibility • Are these numbers divisible by 2, 3, 6, 9? Prove it! • 144 • 647 • 2,294
Today’s Activities • Finish Factor Practice sheet • Journal p. 10 and 14 • Check in • Play Factor Captor • Boards on side counter • Use SRB to follow directions