Lets assume:
1st number[smallest number]: X
2nd number: X+1
3rd number[largest number]: X+2
As their sum is 72 so:
X+X+1+X+2=72
Adding:
3X+3=72
shifting 3 to the other side:
3x=72-3
Subtracting:
3x=69
Dividing:
X=69/3
So:
x= 23
As X represents the smallest number the smallest number is 23
1st number[smallest number]: X
2nd number: X+1
3rd number[largest number]: X+2
As their sum is 72 so:
X+X+1+X+2=72
Adding:
3X+3=72
shifting 3 to the other side:
3x=72-3
Subtracting:
3x=69
Dividing:
X=69/3
So:
x= 23
As X represents the smallest number the smallest number is 23