Subtraction with near-integers: Compute 6888.009 − 487.999 − 87.989 and choose the closest value.

Introduction / Context:
When subtracting several numbers close to integers, it is efficient to combine the subtrahends first, then subtract once. Tiny decimal parts usually shift the result by only a few thousandths, so the nearest ten or hundred is stable.

Given Data / Assumptions:

• Start = 6888.009
• Subtract 487.999 and 87.989

Concept / Approach:
Add the numbers being subtracted: 487.999 + 87.989. Subtract that sum from 6888.009. Compare with the options and pick the closest.

Step-by-Step Solution:

Verification / Alternative check:
Round early to visualize: 6888 − (488 + 88) ≈ 6888 − 576 ≈ 6312. This matches our precise 6312.021 and confirms 6310 as the nearest choice.

Why Other Options Are Wrong:

• 6430, 6390, 6570, 6000: each is farther from 6312 than 6310.

Common Pitfalls:
Subtracting sequentially without grouping (invites small arithmetic slips) or forgetting to carry decimal places correctly when adding 487.999 and 87.989.

Final Answer:
6310