Math 1 · Lesson 1 · Identity and inverse · part 3 of 6
The one sentence to say out loud
If you remember nothing else, remember this one.
The one sentence to say out loud
Finn says
If you remember nothing else, remember this one. Read it out loud, then say it again with your eyes shut.
An inverse is defined by the identity. The opposite of a number is whatever brings it back to zero. The reciprocal is whatever brings it back to one. If you know the do-nothing number for an operation, you already know what the undo partner has to do.