2. In each of the following, just by looking at the given number, circle the number that best approximates it: a) $\frac{73}{142} \approx$ .2 .51 .73 .9 b) $\frac{23}{11} \approx .231$ .49 .8 1.2 2.1 c) $\frac{3}{1,248} \approx .0029$ .3 .67 .948 1.248 d) $\frac{631}{635} \approx$ .31 .635 .97 1.2

Step 1 ：The question is asking for the best approximation of the given fractions. To solve this, we can simply divide the numerator by the denominator for each fraction and compare the result with the given options.

Step 2 ：Calculate the exact values of the fractions: \(\frac{73}{142} = 0.5140845070422535\), \(\frac{23}{11} = 2.090909090909091\), \(\frac{3}{1248} = 0.002403846153846154\), \(\frac{631}{635} = 0.9937007874015747\)

Step 3 ：Compare the exact values with the given options and choose the closest one.

Step 4 ：The closest approximation to \(\frac{73}{142}\) is \(\boxed{0.51}\)

Step 5 ：The closest approximation to \(\frac{23}{11}\) is \(\boxed{2.1}\)

Step 6 ：The closest approximation to \(\frac{3}{1248}\) is \(\boxed{0.0029}\)

Step 7 ：The closest approximation to \(\frac{631}{635}\) is \(\boxed{0.97}\)