And so, for a single bond, say the #C-C# bond in ethane, we would calculate......

#(2-0)/2=1#, i.e. a bond order of #1#.

And for a double bond, say the #C=C# bond in ethylene, we would calculate......

#(4-0)/2=1#, i.e. a bond order of #2#.

And for a double bond, say the #N-=N# bond in dinitrogen, or the #C-=C# bond in acetylene, we would calculate......

#(6-0)/2=3#, i.e. a bond order of #3#.

With practice, you will assign these automatically.....

Non-integral bond orders are certainly possible, but these tend not to appear on undergraduate curricula....i.e. #He_2^+# and #H_2^+# are certainly known molecules, not that you could put the stuff in a bottle, and we could give the bond order as.....

#(2-1)/2=1/2#