Question 431642
A two digit number with 2 different digits has a special property: 
"When the sum of its digits is added to the product of its digits, the result is the number itself."
 What is the smallest number with this property?
:
x = 10's digit
y = units
then
10x+y = the number
:
x + y + xy = 10x + y
xy = 10x - x + y - y
xy = 9x
y = {{{(9x)/x}}}
y = 9 is the units
then 
19 is the smallest number with this property.
:
See if that is true
1 + 9 + (1*9) = 10(1) + 9
:
:
PROBLEM 2:
Six is a perfect number because its factors ( not including 6)add up to itself. What are all the perfect numbers between 20 and 30?
28: 1 + 2 + 4 + 7 + 14