make a mistake

err, blunder

made an error, was wrong, erred

make an error He made a mistake on the math test.

wu3 shi2 bu4 xiao4 bai3 bu4
One that retreats fifty steps laughs at one who does a hundred.
This expression refers to two persons who have both made mistakes, though the mistakes of one may be less serious than the other's. The pot calls the kettle black.