1)15,54 : 4,2=3,7
2)45,8x4,58 + 45,8x5,42 + 4,58x100
=45,8\(\times\)(58+42)+4,58\(\times\)100
=45,8\(\times\)100+4,58\(\times\)100
=4580+458
=5038
47,25 -13,14 - 23,86
=47,25-(13,14+23,86)
=47,25-47,00
=0,25
38,24 x 15,2 + 15,2 x 61,76
=15,2x(38,24+61,76)
=15,2x100,00
=1520