hard tu reed em tiny characters abuv & belo, but
log10(20)=1.30102999...this impli log10(2)=0.3010999
log10(10)=1 bi defineashun
log10(5)=0.69897000
5=10/2, so spekt log(5)=log(10) -log(2)
=1-0.3010999
=0.698901, kloes tu abuv number=0.69897
seem tu be a littel round off errem