Soln: 4 ×3 ×10 5+6

= 12×1011

= 1.2 ×101× 1011

=1.2 ×1011+1

=1.2× 1012 Ans.

Solution: 4.215×10-2+3.2×10-2

=(4.215+3.2)×10-2

= 7.415×10-2