When is four minus one equal to five? brain twists

When is four minus one equal to five? brain twists

Blushing
I'm here to make trouble
Wrong answer 1 is equal to five
I have four of them, and one of them is equal to five
3. Open your hand and close your thumb to the palm of your hand. Hey, hey, "4-1" is still five fingers
Bo Jun smiles*^^*