Addition and subtraction word problems 2

Problem

There are 20 ants eating some crumbs. 1 was a red ant and the rest were black ants.
How many were black ants?
  • Your answer should be
  • an integer, like 6
  • an exact decimal, like 0, point, 75
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
black ants