Round off the following numbers to the nearest 100 and perform the calculations: a) 287, b) 765, c) 423, d) 1392, e) 342, f) 550. Also, calculate: a) 16x17, b) 21x51, c) 43x25, d) 30x29, e) 38x17.

Here are the solutions to your problems: 1. Round off to the nearest 100 a) 287 The tens digit is 8, which is 5 or greater, so round up the hundreds digit. 287 ≈ 300 b) 765 The tens digit is 6, which is 5 or greater, so round up the hundreds digit. 765 ≈ 800 c) 423 The tens digit is 2, which is less than 5, so keep the hundreds digit the same. 423 ≈ 400 d) 1392 The tens digit is 9, which is 5 or greater, so round up the hundreds digit. 1392 ≈ 1400 e) 342 The tens digit is 4, which is less than 5, so keep the hundreds digit the same. 342 ≈ 300 f) 550 The tens digit is 5, which is 5 or greater, so round up the hundreds digit. 550 ≈ 600 2. Calculation a) Example: 16 × 17 16 × 17 = 272 b) 21 × 51 Step 1: Multiply the numbers. 21 × 51 = 1071 The answer is 1071. c) 43 × 25 Step 1: Multiply the numbers. 43 × 25 = 1075 The answer is 1075. d) 30 × 29 Step 1: Multiply the numbers. 30 × 29 = 870 The answer is 870. e) 38 × 17 Step 1: Multiply the numbers. 38 × 17 = 646 The answer is 646. That's 2 down. 3 left today — send the next one.