Calculate Missing Production Percentage: 49 of 85 Calculators Made

To calculate the percentage of the daily calculator production that has not yet been achieved, follow these steps:

• Step 1: Determine the number of calculators left to be produced:
  Total required: $85$ calculators
  Produced so far: $49$ calculators
  Remaining = $85 - 49 = 36$ calculators
• Step 2: Compute the percentage of unachieved production with respect to the total required:
  $\left(\frac{36}{85}\right) \times 100\% = \frac{3600}{85} \approx 42.35\%$
• Step 3: Round to the nearest whole number:
  Approximately $42.35\%$ rounds to $43\%$.

Therefore, approximately 43% of the necessary daily calculator production has not yet been achieved.

Thus, the correct answer is choice $43\%$.