Let the three consecutive numbers are x, x+1 and x+2. According to given conditions;
First number + Second number + Third number = 99
x + (x+1) + (x + 2) = 99
x + x + 1 + x + 2 = 99
3x + 3 = 99
3x = 99-3
3x= 96
x= 32
First number = x= 32
Second number= x + 1= 32 + 1 = 33
Third number = x + 2= 32 + 2= 34
First number + Second number + Third number = 99
x + (x+1) + (x + 2) = 99
x + x + 1 + x + 2 = 99
3x + 3 = 99
3x = 99-3
3x= 96
x= 32
First number = x= 32
Second number= x + 1= 32 + 1 = 33
Third number = x + 2= 32 + 2= 34