Can 73 × 0.98 be simply calculated

Can 73 × 0.98 be simply calculated


can
73×0.98
=73×(1-0.02)
=73×1-73×0.02
=73-1.46
=71.54



A number of 18.6 times his 5.7 times more than 2.58, find this number


18.6x-5.7x=2.58
x=0.2