Answer:
4.25 × 10^-4
Step-by-step explanation:
0.00045-2.5x10^-5
= (4.5 × 10^-4) - (0.25 × 10¹ × 10^-5)
= (4.5 × 10^-4) - (0.25 × 10^{1-5} )
= (4.5 × 10^-4) - (0.25 × 10^-4)
= (4.5 - 0.25) × 10^-4
= 4.25 × 10^-4
