50.007 in standard form?
Writing a number in standard form simply means to express the number in its 'normal' form. Therefore, your example is written in standard form.
Unless you are not in the USA, in which case
Standard form (also known as "standard index form" or "scientific notation") requires a single non-zero digit before the decimal point and a multiplier of a power of 10 which gets the decimal point back to where it was in the original number. To calculated the power of the ten count how many digits the decimal point needs to move; if it needs to move to the left make it negative:
50.007 = 5.0007 × 10¹