Respuesta :
if 1 book costs 1.99.....then 4 books cost : (4 * 1.99) = $ 7.96 <==
[tex]1.99(4) = 4(2-0.01)[/tex]
[tex]4(2-0.01) = 8 - 0.04 = 7.96[/tex]
[tex]4(2-0.01) = 8 - 0.04 = 7.96[/tex]