Turn the wrong equation into the correct | Matchstick puzzle 2+2=1

I was completely stumped by this last puzzle, but maybe you’ve already figured it out? Please share your knowledge in the comments below!

You will see answers to these puzzles:-

1) Matchstick puzzle 2+5=9
2) Matchstick puzzle 1+5=0
3) Matchstick puzzle 8-4=2
4) Matchstick puzzle 6+4=4
5) Matchstick puzzle 2+2=1