88
-- List the digits that are used to write the number. -- Add up the list.
The numbers for which the sum of its proper factors is 1 less than the number is the powers of 2; less than 50 these are: 2, 4, 8, 16 & 32.
3 13 23 43 53 73 83
1, 11, 21, 31, 41. 1 is not a prime number.
8
6677
-- List the digits that are used to write the number. -- Add up the list.
The numbers for which the sum of its proper factors is 1 less than the number is the powers of 2; less than 50 these are: 2, 4, 8, 16 & 32.
3 13 23 43 53 73 83
1, 11, 21, 31, 41. 1 is not a prime number.
Nope, look at 1000, this is a 4 digit number and we can't list it with 1,2,3, and 4
The list of factors of a number is a list of numbers that divide evenly into it. A list of multiples of a number is just a list of numbers that the first number divides. Example Factors of 6: 1,2,3,6 Multiples of 6: 6,12,18...
8
When you are finding common factors, one method is to list the factors.
The hundreds digit is 2; the tens digit is 5; the ones digit is 8; the tenths digit is 1; the hundredths digit is 7; the thousandths digit is 6.
The proper factors of a number are all the factors less than itself, so the proper factors of 126 are 1, 2, 3, 6, 7, 9, 14, 18, 21, 42, and 63. In some cases, the number 1 is excluded from the list of proper factors, too.
1 has one factor