Answer:
0.05 cm
Step-by-step explanation:
The least-significant digit in the given measurement is the one in the 0.1 cm number place. The "greatest possible error" is half the value of that number place, so is ...
(0.1 cm)/2 = 0.05 cm . . . . "greatest possible error"
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For questions of this sort, we make the (not always practical) assumption that the measurement is rounded perfectly to the nearest 0.1 cm.
There is a thousand answer to this problem.
Let's do the simplest one here.
f(x) or y = x - 1
f(x) or y = x + 1
f(x) or y = -x
Wait, would this count as a solution? : See the second attachment
20 can be divided by 2 twice, with 5 remaining
20 can be divided by 4 once, with 5 remaining
20 can be divided by 5 once, with 4 remaining
20 can be divided by 10 twice
20 can be divided by 20 once
hope this helps