Answer:
0.4x10'20
Step-by-step explanation:
for the scientific notation u need to move the decimal to make a small number.
0.0000000000000000000004 ---> 0.4
move the decimal 20 spaces to the right
(formula:(number times 10(expontent 'the moved spaces'))
0.4x10'20
(the 20 is the expontent)