Please help, I don't know how to do this T T

Answer:
There are only 5 zeros because the 10 to the power of 6 is being multiplied with a decimal.
Step-by-step explanation:
10 to the power of 6 is 1000000
1000000 x 3.5
3500000
the decimal point "takes" a 0 because it is in the tenth place. If it was the hundredths it would take 2 and etc.