YOU SAID:

it takes fewer muscles to smile than it does to frown

INTO JAPANESE

顔をしかめるよりも笑顔に必要な筋肉が少ない

BACK INTO ENGLISH

There are fewer muscles needed to smile than to resyle the face.

INTO JAPANESE

笑顔を見せる筋肉は、顔をリシレにするよりも少ない。

BACK INTO ENGLISH

The muscles that make you smile are less than your face.

INTO JAPANESE

笑顔になる筋肉は顔より少ない。

BACK INTO ENGLISH

The muscles that make you smile are less than your face.