100%-0,5%=99,5%
100%-1%=99%
100% -99,5% × 99%=100/100-9850,5/10000=(10000-9850,5)/10000=
=149,5/10000=0,01495=1,495%
verificare
consideram L=2 m l=1,5m A= 3,0 m²
2 x1%=0,02 2-0,02=1,98 cm
1,5 x 0,5%=0,00075 1,5-0,0075=1,4925 cm
A=1,98 x 1,4925 =2,95515 cm²
2,95515:3=0,98505 =98,505%
100%-98,505%=1,495%