x = {'a': 3, 'b': 2, 'c':7}

and, we want to add the values i.e. 3 + 2 + 7 = 12.

Here are the three ways to add the values.

### Using list comprehension

>>> x = {'a': 3, 'b': 2, 'c':7}

>>> sum([i for i in x.values()])

12

>>> sum([i for i in x.values()])

12

### Using for loop I

>>> x = {'a': 34, 'b': 2, 'c':7}

>>> total = 0

>>> for i in x.values():

total += i

>>> total = 0

>>> for i in x.values():

total += i

### Using for loop II

>>> x = {'a': 34, 'b': 2, 'c':7}

>>> total = 0

>>> for key in x.keys():

total += x[key]

>>> total = 0

>>> for key in x.keys():

total += x[key]