Dani brings 2.5 x 12 = <<2.5*12=30>>30 cupcakes.
She needs this many cupcakes to feed everyone in class 27 + 2 = <<27+2=29>>29.
With the 3 students calling in sick, there are this many people in class today 29 - 3 = <<29-3=26>>26.
There are this many cupcakes left after everyone gets one 30 - 26 = <<30-26=4>>4 cupcakes.
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