Matea recorded that water levels in one part of the river fell 1.05 millimeters per year for 2,48 years. Describe how
you could estimate the total variation in water level.

The decrease of the decimal rate -1.05 mm/year can be rounded to -1. You don’t need to round 2.48 because you’re multiplying by -1. Since -1.05 is negative and rounded to a greater value, the estimate could be adjusted to a slightly lesser value, maybe -2.5 or -2.6.