These numbers are in order of size. The smallest number is first.
Verify this.
420×10−2 420 \times 10^{-2} 420×10−2 42×100 42 \times 10^0 42×100 4.2×102 4.2 \times 10^2 4.2×102 0.042×105 0.042 \times 10^5 0.042×105261 exam-style questions on OCR GCSE Maths Standard Form. Each one has a worked solution and a mark scheme showing where the marks go.