Answer
a, $110.6$
b, $41.4$
c, $183.3$
d, $1.22$
Work Step by Step
When determining the correct number of significant figures in the results of addition and subtraction calculations, the answer must be rounded off to the same precision as the least precise number in the calculations
a, 87.6 and/or 2.3 is the least precise number-to the tenths place
so our answer should be 110.6
b,43.7 is the least precise number-to the tenths place
so our answer should be 41.4
c, 89.6 is the least precise number-to the tenths place
so our answer should be 183.3
d, 6.99 is the least precise number-to the hundredth place
so our answer should be 1.22