51. Evaluate each of the following, and write the answer to
the correct number of significant figures.
a. 97.381 + 4.2502 + 0.99195
b. 171.5 + 72.915 – 8.23
c. 1.00914 + 0.87104 + 1.2012
d. 21.901 – 13.21 - 4.0215