Past papers › JAMB 1987 · UME › Question 13 Question JAMB General Maths 1987 Objective Approximation & error Indices & standard form Approximation & error, Indices & standard form
Instead of writing 35 6 \frac{35}{6} 6 35
A 0.003 B 3.0 × 10 − 3 3.0 \times 10^{-3} 3.0 × 1 0 − 3 C 0.3 × 10 2 0.3 \times 10^2 0.3 × 1 0 2 D 0.3 × 10 − 3 0.3 \times 10^{-3} 0.3 × 1 0 − 3
Worked solution (try it first) Divide:
35 6 = 5.8333 … \frac{35}{6} = 5.8333\ldots 6 35 = 5.8333 … To 3 significant figures this is 5.83.
To 3 decimal places it is 5.833.
The error is
5.833 − 5.83 = 0.003 5.833 - 5.83 = 0.003 5.833 − 5.83 = 0.003 .
In standard form that is
3.0 × 10 − 3 3.0 \times 10^{-3} 3.0 × 1 0 − 3 , option B.
Watch out
0.003 (option A) is the right size but not in standard form, which needs a number from 1 to 10 times a power of 10. 0.3 × 10 − 3 0.3 \times 10^{-3} 0.3 × 1 0 − 3 Report a problem with this question