(abcd)(abcd)(abcd)(abcd) \displaystyle {\displaystyle{a\over b}\choose \displaystyle{c\over d}} \textstyle {\displaystyle{a\over b}\choose \displaystyle{c\over d}} \scriptstyle {\displaystyle{a\over b}\choose \displaystyle{c\over d}} \scriptscriptstyle {\displaystyle{a\over b}\choose \displaystyle{c\over d}}