a)
2,4×4,2-3,2 ÷4/5=10,08-32/10 ×5/4=
=10,08-8/2=10,08-4=6,08
sau
2,4×4,2-3,2 ÷4/5=24/10×42/10-32/10 ×5/4=
=12/5×21/5-8/2=252/25-4=(252-100)/25=152/25=6 intregi 2/25=6,08
b)4,5+31/10 ×2,6=45/10+31/10 ×26/10=45/10+806/00=(450+806)/100=
=1256/100=12,56
sau
4,5+31/10 ×2,6=4,5+3,1 ×2,6=4,5+8,06=12,56
