What are the missing numbers in this sequence? Negative 20, blank, zero, 10, 20, blank, blank.
We have a spot in the sequence where we’re given three consecutive numbers. We go from zero to 10 and then from 10 to 20. To get from zero to 10, we add 10. And then from 10 to 20, we add 10. If we wanted to move in the opposite direction, we could subtract 10, which means our first missing value would be zero minus 10. And that’s negative 10.
To check our pattern, we can go to the left from negative 10 to negative 20. Negative 10 minus 10 does equal negative 20. And for our final two solutions, we’ll need to add 10 to 20, which is 30, and then add 10 to 30, which is 40. In this sequence, our missing values were negative 10, 30, and 40.