Answer:
≈ 20
Step-by-step explanation:
2.65 ≈ 3 ( to 1 significant figure )
4.1758 ≈ 4 ( to 1 significant figure )
7.917 ≈ 8 ( to 1 significant figure )
Then approximate calculation is
3 × 4 + 8 = 12 + 8 = 20