The possible numbers greater than 43 and less than 52 are :
44, 45,46, 47, 48, 49, 50 and 51
Now let us find sum of digits of each one of these,
44 : 4+4 = 8
45: 4+5 = 9
46: 4+6 = 10
47: 4+7 = 11
48: 4+8 + 12
49: 4+9 = 13
50: 5+0 =5
51: 5+1= 6
Out of these 44 is the number whose digits add up to give 8.
Answer: 44