Evaluate 0.0025 × 2.5 × 102 to 2 significant figures.

Analyze the question: We need to multiply 0.0025 × 2.5 × 10², then round to 2 significant figures.

The "102" is almost certainly 10² (the superscript was lost in formatting), and the options also have lost superscripts (10-3 means 10⁻³, and so on).

Step 1: Multiply the numbers 0.0025 × 2.5 = 0.00625

Step 2: Multiply by 10² 0.00625 × 100 = 0.625

Step 3: Round to 2 significant figures 0.625 → 0.63 (the third significant figure is 5, so we round up)

Step 4: Write in standard form 0.63 = 6.3 × 10⁻¹

Check the options:

• A. 0.625 × 10⁻³ = 0.000625 (wrong value, and not 2 s.f.)
• B. 0.63 × 10⁻² = 0.0063 (wrong)
• C. 6.25 × 10⁻³ = 0.00625 (this is the answer if the ×10² is ignored, and it is 3 s.f.)
• D. 6.3 × 10⁻² = 0.063 (wrong)
• E. 6.3 × 10⁻¹ = 0.63 (correct)

Tip: When a question gives powers of 10, convert everything to ordinary numbers first and then round. For standard form, the first number must be between 1 and 10, so 0.63 becomes 6.3 × 10⁻¹. Also, when rounding to significant figures, a 5 in the next digit means round up.