What is equal to -10?

Answer 1

Ten dekagrams is equal to 100 grams since each dekagram is equal to 10 grams. However, 100 grams is only equal to just less than a quarter of a pound.

Answer 2

There are infinitely many possible answers.

1-11, 2-12, 3-13, 4-14 and so on.

then

1.1-11.1, 1.2-11.2, 1.3-11.3 and so on.

You can continue with numbers to 2 decimal points, 3 dp, 4 dp and so on to infinitely many dps.

So far there have been pairs of numbers. Next consider triplets:

1+1-12, 1+2-13 and so on and again with numbers to 1, 2, ... , infinitely many decimal places.

And that can be extended to quartets, quintets, and so on all the way to infinitely large sets.

All that is with addition and subtraction. But is is also possible to generate infinitely many answers based on multiplication, division, exponentiation, logarithms, and so on.

Answer 3

10 is equal to 10. It is not equal to any other number.

Answer 4

Any number that is one more than nine.