Simplification and Approximation

Calculate each part separately: 51% of 4986 ≈ 2543 (since 50% is 2493, plus 1% is 49.86). 3/7 of 899 ≈ 385 (since 900/7 ≈ 128.6, times 3 ≈ 385.7). Subtract: 2543 - 385 = 2158. Among options, 2165 is closest.

Approximate: 448 ÷ 28 × 5. 448 ÷ 28 = 16 (since 16×28=448). Then 16 × 5 = 80. Using approximations (447.75 ≈ 448, 4.99 ≈ 5) gives us 80, which matches Option D.

The expression is: 73² - 16³ = ?% of 399. Calculate 73² = 5329. Calculate 16³ = 4096. Difference: 5329 - 4096 = 1233. Now: 1233 = (x/100) × 399, so x = 1233 × 100 / 399 ≈ 309.02. Closest to 310, which is Option D.

Calculate 148² - 25³ = 21904 - 15625 = 6279. Then 6279 = 499% of x, so x = 6279 / 4.99 ≈ 1258.3. Among options, 1250 (Option A) is the closest approximation since 1250 × 4.99 = 6237.5 and 1258.3 is approximately 1250.

Calculate 159 × 43 = 6837 and 37 × 57 = 2109. Difference = 6837 - 2109 = 4728. We need ?² = 4728, so ? = √4728 ≈ 68.76. Among options, 70 (Option D) is closest since 70² = 4900 and 68² = 4624; 4728 is nearer to 4900.

Calculate step by step: 87 × 34 = 2958, 46 × 37 = 1702. Then: 2958 - 1702 + 132 = 1256 + 132 = 1388. Now: 1388 = ?% of 599. Solving: ? = (1388/599) × 100 ≈ 2.317 × 100 ≈ 231.7%. Among the options, 240 is the closest approximation.

Calculate 23% of 6783 ≈ 0.23 × 6800 = 1564. Calculate 57% of 8431 ≈ 0.57 × 8400 = 4788. Sum: 1564 + 4788 = 6352. Among options, 6360 (option E) is the closest approximation.

Approximate: 335.01 × 244.99 ÷ 55 ≈ 335 × 245 ÷ 55. 335 × 245 = 82075. 82075 ÷ 55 ≈ 1492. Among options, 1490 (option A) is the closest approximation.

First simplify: 123 x 79 = 9717 and 25 x 33 = 825. Then 9717 - 825 = 8892. Let this be x% of 451, so x/100 x 451 = 8892. Solving: x = 8892 x 100 / 451 = 889200/451 ≈ 1971.6. Rounding gives approximately 1980. The key is to compute accurately and round appropriately.

185% of 1359 = 1.85 × 1359 ≈ 2514. 18.5% of 1319 = 0.185 × 1319 ≈ 244. Total ≈ 2514 + 244 = 2758, closest to 2760. Option C matches.

LHS = 89 × 63 + 42 × 99 = 5607 + 4158 = 9765. RHS = 115 × ? = 9765. Therefore ? = 9765 ÷ 115 = 84.87 ≈ 85.

172% of 269 = 1.72 × 269 = 462.68 ≈ 463. 24% of 114 = 0.24 × 114 = 27.36 ≈ 27. Equation: 463 ÷ 27 = 17.15 ≈ 17.

Round 570.80 to 571 and 9.09 to 9 for estimation: 571 × 9 = 5139. Then 230855 ÷ 5139 ≈ 44.9, which rounds to 45. This approximation method works well since we're asked for an approximate value.

33.33 is approximately 100/3 and 333.3 is approximately 1000/3. Multiplying these gives (100 × 1000) / (3 × 3) = 100000/9 ≈ 11111.11. Among the options, 11110 is the closest approximation.

1.71% of 1606 is approximately 27.5, and 0.705% of 1005 is approximately 7.1. Adding these gives about 34.6, which rounds to 35. The key is to calculate each percentage separately and then sum.