Rules for divisibility 2 + 1 Math Rocks! - YouTube Divisibility Rules Rules for divisibility 2 + 1 Math Rocks! - YouTube

Summary of Divisibility Rules Number Divisibility Rules 10 5 2 3 9 6 4 8

Divisibility by 4 Multiply 10’s digit by 2 Add this product to 1’s digit If the sum is divisible by 4 then so is the number Example: 4696 9 x 2 = 18 18 + 6 = 24 If 24 is divisible by 4 then so is the original number

Divisibility by 8 Multiply 100’s digit by 4 Multiply 10’s digit by 2 Add product of above numbers to 1’s digit If the sum is divisible by 8 then so is the number Example: 47724 7 x 4 = 28 2 x 2 = 4 28 + 4 = 32 If 32 is divisible by 8, then so is the original number

Common Multiples We need to sell 100 hot dogs! Buns come in packs of 8 Wieners come in packs of 12 What do we do?????????

Common Factors What factors do the numbers 120 and 135 have in common?