calculer et donner l ecriture sientifique A=138X10^13_0,62X10^15 B=12X10^5X40X10^-7 8X10^-9 C=81X10^-5X14X(10^2)^3 7X10^4

A= 138 x 10^13 - 0,62 x 10^15

A= 1,38 x 10^15 - 6,2 x 10^14

A= 1380000000000000 - 620000000000000

A= 760000000000000

A= 7,6 x 10^14

B= (12 x 10^5 x 40 x 10^-7) / 8 x 10^-9

B= (12 x 40) / 8 x (10^5 x 10^-7) / 10^-9

B= 480/8 x 10^-2/10^-9

B= 60 x 10^7

B= 600 000 000

B= 6 x 10^8

C= (81 x 10^-5 x 14 x (10^2)^3) / 7 x 10^4

C= (81 x 14) / 7 x (10^-5 x (10^2)^3) / 10^4

C= 1134/7 x (10^-5 x 10^6) / 10^4

C= 162 x 10^1/10^4

C= 162 x 10^-3

C= 0,162

C= 1,62 x 10^-1