How To Calculate Sum of Digits Of a 3-Digit Number

#CALCULATE THE SUM OF DIGITS OF A 3-DIGIT NUMBER

print('SUM OF DIGITS OF A 3-DIGIT NUMBER')
num=a=b=c=ttl=0
num=int(input('Enter a 3-Digit Number = '))#123
if(num<100 or num>999):
     print (num,'is INVALID INPUT')
else:
     a=num%100
     b=(num-a)/100
     c=num%10#123%10=3
     d=(num-(b*100)-c)/10
     ttl=b+c+d
     print ('The Sum Total =',ttl)

Made By :-

         Nilay Saraf