The question shown on the right is quite well answered even though it is on the formative-only practice assessment. Errors when they do occur are mostly as I’d have predicted – 4.5% of responses give the wrong sign in the power of ten and 2.5% of responses raise 2.6 rather than 10 to the correct power. Then a small number give answers that are 10 times too big or 1o times too small or fail to use the superscript function correctly.
However a comparison of the different variants of this question is interesting. A variant where students have to express 0.1578 in scientific notation appears to cause significantly more difficulties than the one shown above. At one level this is the opposite from what you might have expected, because it is all too easy to miscount the zeroes in 0.00026. It appears that ten to the minus one is a difficult power to understand.