11. =38420000 Step By Step: 3.9(107)−5.8(105)=(3.9)(10000000)−5.8(105)=39000000−5.8(105)=39000000−(5.8)(100000)=39000000−580000=38420000
12. =2520000 Step By Step: 6.2(105)+1.9(106)=(6.2)(100000)+1.9(106)=620000+1.9(106)=620000+(1.9)(1000000)=620000+1900000=2520000
13.=999260000000 Step By Step: (1012)−7.4(108)=(1)(1000000000000)−7.4(108)=1000000000000−7.4(108)=1000000000000−(7.4)(100000000)=1000000000000−740000000=999260000000
14. =225 Step By Step: 4.5−10−1=4.5−110=225
7(10−4)=71000 Step by Step: 7(10−4)=7(110000)=710000