Question 851668
the third must end in 1
1xx1
first must be one of these
11,22,33,44,55,66,77,88,99
second must be 
1y1,2y2,3y3
4y4,5y5,6y6
7y7,8y8,9y9

the first and second must add up a number ending in 1
the first and second must add up a number beginning with  1 
the first and second must add up to a number greater than 1000
9 and 2
greater 901 plus 99 is a four digit number
since it begins with 1 it must end in 1

5y5+66 is not 4 digits
so it must 9y9 and 22=1xx1
909+22+10x=1001+z
931+10a=1001+b,
b=100c+10c
c<10
a<10
b>10
c=0
999+22=1021
989+22=1011
979+22=1001
bingo