4th grade math patterns 18250, 18500, 19000, 20000 what's the next number?

22000

The number that's being added in the sequence increases by 2x.

250 * 2 = 500, which is added to 18500 to equal 19000.

500 * 2 = 1000, which is added to 19000 to equal 20000.

1000 * 2 = 2000, which added to 20000 equals 22000.