Can someone help me please

Answer:
9) 392,400
10) 92,000,000,000,000,000
11) 0.004391
12) 0.0006825
Step-by-step explanation:
9) 3.92400 move the decimal point 5 times to the right
10) 9.2 add 15 zeros on the right
11) 4.391 add 3 zeros on the left side
12) 6.825 add 4 zeros to the left side