3 numbers that add up to 45 = 48
If you can add the integers and they add up to a number divisible by 3, then the number is divisible by 3.
27
33 and 39The way to do this is to see which odd numbers between 30 and 40 have digits that add up to a multiple of 3 since this is the test to see if a number is divisible by 3.So 33 has digits that add to 6 since 3+3=6 and 33 is oddAlso, 39 has digits that add up to 12 since 3+=12 and 39 is odd.36 has digits that add to 9, but it is even so we discard it.
189
You are 45. Remember, if a number is divisible by 5, then it must either end in 0 or 5. Therefore, since your digits are one apart, your only possibilities are 10, 45, and 65. Now, if a number is divisible by 3, the digits of that number add up to a number that is divisible by three. Of your three possibilities, this only works with 45 since 4 + 5 = 9 and 9 is divisible by 3. Hence, you are 45.
-144
You line up the last numbers and then add it!
45
If the digits of a number add up to a multiple of 3, then the number can be divided by 3. For example, the digits of 852 add up to 8 + 5 + 2 = 15. Since 15 is divisible by 3, 852 is divisible by 3.
If the digits of the number you're dividing by 3 add up to a multiple of 3, the whole number is divisible by 3 and there will be no remainder. If they don't add up to a multiple of 3, there will be a remainder.
48