Sure you do !
80% means 0.80 .
91% means 0.91
"of" means "times"
For the first performance, (0.80 x 600) = 480 were sold.
For the second performance, (0.91 x 600) = 546 were sold.
Total for both performances = (480 + 546) = 1,026 tickets .
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Here's a different, smooth, cool, exhilarating, fun way to do it,
that makes it look like you're actually catching on in math:
(80% of 600) plus (91% of 600) = 171% of 600 .
171% means 1.71
1.71 x 600 tickets = 1,026 tickets
