19.9*18 -19.9 *16 +30.1 *18 -30.1 *16
19,9*18-19,19*16=19,9*2=19,9×19,9=396,01
30,1*18-30,1*16=30,1*2=30,1×30,1=906,01
396,01+906,01=1302,02
1)19,9*18-19,19*16=19,9*2=19,9×19,9=396,01
2)30,1*18-30,1*16=30,1*2=30,1×30,1=906,01
3)396,01+906,01=1302,02