Question

which number is the smallest?
a ( 1.25 \times 10^{-1} )
b ( 1.68 \times 10^{-5} )
c ( 1.57 \times 10^{-2} )
d ( 1.75 \times 10^{-1} )

Explanation:

Step1: Convert to decimal

• For A: $1.25\times10^{-4}=1.25\div10000 = 0.000125$
• For B: $1.68\times10^{-5}=1.68\div100000 = 0.0000168$
• For C: $1.57\times10^{-2}=1.57\div100 = 0.0157$
• For D: $1.75\times10^{-1}=1.75\div10 = 0.175$

Step2: Compare decimals

Compare $0.000125$, $0.0000168$, $0.0157$, $0.175$. We can see that $0.0000168$ (from B) is the smallest.

Answer:

B. $1.68\times10^{-5}$