Respuesta :

its the last answer because you would move the decimal to the right three places 
[tex]1.26\cdot10^{-3}-7.003\cdot10^{6}=1.26:10^3-7.003\cdot10^6=\\\\=1.26:1,000-7.003\cdot1,000,000=0.001260-7,003,000[/tex]