Storing scientific notations using $4-$bit system: $\backslash$times $,=10$

First bit for sign, second$/$third bit for the m$,$ last bit for c$.$

With $2$ bits, the range for m is: $11,10,01,00,$ which corresponds to:

$21+20=3,21=2,20=1,0,$ so m can have values of $3,2,1,0$

With $1$ bit for c$,$ c can be either $0$ or $1.$

Write out the dynamic range for $4-$bit with $10-$base.