To round a number, look at the digit to the right of the place you are rounding to.
• Nearest ten: look at ones digit (5). 5 ≥ 5, so round up → 918640
• Nearest hundred: look at tens digit (3). 3 < 5, so round down → 918600
• Nearest thousand: look at hundreds digit (6). 6 ≥ 5, so round up → 919000
Final Answer: 918640, 918600, 919000