Math Journal Notes Unit 4

A number is divisible by.... 2 if it is an even number 3 if the sum of the digits is divisible by 3 5 if it ends in a 0 or 5 6 if it is also divisible by BOTH 2 and 3 7 take the last digit, double it, and subtract it from the rest of the number. If that number is divisible by 7, you can divide by 7. 8: If the last three digits of a whole number are divisible by 8, then the entire number is divisible by 8 9 if the sum of the digits is divisible by 9 10 if it ends in a 0 1/18/17 Divisibility Rules Divisible / Divisibility: Can be divided by

and giving it to the other addend to make the problem easier to solve. 11/17/16 Give and Take Strategy The give and take strategy involves taking “some amount” from one of the addends and giving it to the other addend to make the problem easier to solve. Example: Solve 197 + 78 + 3 = 200 -- 3 = 75 __________________ 275 Think: Which addend, 197 OR 78, is closer to a multiple of 1, 10, 100, 1000, etc.? 197 is close to 200 so I: need to TAKE 3 from 78 and GIVE it to the 197 to make 200 78 minus 3 is 75 Add 200 to 75 to equal 275

12/1/16

To SUBTRACT decimals To ADD decimals What about zeros as placeholders? 12/5/16 To ADD decimals What about zeros as placeholders?

12/6/16

1/10/17

2/2/17