a)724=7•10²+2•10 la puterea1+4
b)2.387=2•10 la puterea3+3•10²+8•10 la puterea1+7
c)54.013=5•10 la puterea4+4•10 la puterea3+0•10²+1•10 +3
d)21.209=2•10 la puterea4+1•10 la puterea3+2•10²+0•10+9
e)430.067=4•10 la puterea 5+3•10 la puterea4+6•10+7
a7b=a•10²+7•10+b