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How to Round Whole Numbers A Number Line When rounding number, some times it helps to remember and to use a number line. | 0 | | 100 200 | 1 000 000 | | | | | | | | | | 10 20 30 40 50 60 70 80 90 100 | 300 | 400 | 500 | 2 000 000 | 600 | 700 | 800 | | 900 1000 | 3 000 000 BASIC RULES 1. If the number to the RIGHT of the Rounding Number is 5 or more (5, 6, 7 8 or 9) then the LEFT (Rounding Number) number goes UP by ONE place. 2. If the number to the RIGHT of the Rounding Number is 4 or less (4, 3, 2, 1 or 0) then the LEFT (Rounding Number) number remains the SAME. 3. Every number AFTER the Rounding Number becomes 0. 4. Everything BEFORE the Rounding Number remains the same. 5. If the Rounding Number is a 9 and it goes up by one, then a 0 is placed in the Rounding Number Place and 1 is moved to the next place to the LEFT. (same as carrying in adding) How to Round Whole Numbers to the Tens Place Example: Round 78 to the nearest tens place | | | | | | | | | | 78 80 70 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the tens place 78 How to Round Whole Numbers to the Tens Place Example: Round 78 to the nearest tens place 2. Look to the right of the place you want to round to, Look here Now look to the right of the 78 tens place - If the digit is 5, 6, 7, 8 or 9 – the digit in the tens place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the tens place STAYS THE SAME The 7 in the tens place goes up by 1 to 8 78 80 How to Round Whole Numbers to the Tens Place Example: Round 78 to the nearest tens place 3. Next, the digits to the right of the rounding place become zero. Now the 8 becomes zero 78 becomes 80 4. Anything to the left of the rounding place remains the same. So 78 rounded to the nearest tens place is 80 How to Round Whole Numbers to the Tens Place Example: Round 123 to the nearest tens place | | | | | | | | | | 130 120 123 To Round: Look to the right On the left 123 Here is the tens place 3, so the 2 in the tens place stays the same. On the left hand side, all stays the same 123 rounds to 120 How to Round Whole Numbers to the Tens Place Example: Round 1 099 to the nearest tens place | | | | | | | | | | 1090 1099 1100 To Round: 1099 Here is the tens place with 9 to its right The 9 in the tens place goes up by one. **But, 9 goes to 10 and we only have one place 1100 So we need to move over one more place to the left adding 1 to the hundreds place and 0 to the tens place. All on right changes to zero. 1 099 rounds to 1 100 How to Round Whole Numbers to the Tens Place Example: Round the following to the nearest tens place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 __2 65 234 2 343 45 678 65 723 199 789 1 222 222 0 70 230 2 340 45 680 65 720 199 790 1 222 220 Look to the value of the place to the right of the tens place Round the following numbers to the nearest tens place. a) 45 b) 67 a) 50 b) 70 c) 123 c) 120 d) 456 d) 460 e) 890 e) 890 f) 1232 f) 1 230 How to Round Whole Numbers to the Hundreds Place Example: Round 145 to the nearest hundreds place | | | | | | | | | | 200 100 145 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the hundreds place 145 How to Round Whole Numbers to the Hundreds Place Example: Round 145 to the nearest hundreds place 2. Look to the right of the place you want to round to, Now look to the right of the tens place 145 - If the digit is 5, 6, 7, 8 or 9 – the digit in the hundreds place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the hundreds place STAYS THE SAME The 1 in the hundreds place stays the same 145 100 How to Round Whole Numbers to the Hundreds Place Example: Round 145 to the nearest hundreds place 3. Next, the digits to the right of the rounding place become zero. Now the 4 and 5 becomes zero 145 becomes 100 4. Anything to the left of the rounding place remains the same. So 145 rounded to the nearest hundreds place is 100 How to Round Whole Numbers to the Hundreds Place Example: Round the following to the nearest hundreds place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 __2 _65 234 2 343 45 678 65 723 199 789 1 222 222 0 100 200 2 300 45 700 65 700 199 800 1 222 200 Look to the value of the place to the right of the hundreds place Round the following numbers to the nearest hundreds place. a) 49 a) 0 b) 136 b) 100 c) 293 c) 300 d) 456 d) 500 e) 1 890 e) 1 900 f) 12 345 f) 12 300 How to Round Whole Numbers to the Thousands Place Example: Round 9 871 to the nearest thousands place | | | | | | | | | | | 9000 9 871 10 000 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the thousands 9 871 How to Round Whole Numbers to the Thousands Place Example: Round 9 871 to the nearest thousands place 2. Look to the right of the place you want to round to, Now look to the right of the thousands place 9 871 - If the digit is 5, 6, 7, 8 or 9 – the digit in the thousands place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the thousands place STAYS THE SAME The 9 in the thousands place goes up by 1 9 871 10 000 How to Round Whole Numbers to the Thousands Place Example: Round 9 871 to the nearest thousands place 3. Next, the digits to the right of the rounding place become zero. Now the 8,7 and 1 becomes zero 9 871 becomes 10 000 4. Anything to the left of the rounding place remains the same. So 9 871 rounded to the nearest thousand place is 10 000 How to Round Whole Numbers to the Thousands Place Example: Round the following to the nearest thousands place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 ___2 _ _65 _234 2 343 45 678 65 723 199 789 1 222 222 0 0 0 2 000 46 000 66 000 200 000 1 222 000 Look to the value of the place to the right of the thousands place Round the following numbers to the nearest thousands place. a) 1 234 a) 1 000 b) 78 902 b) 79 000 c) 12 666 c) 13 000 d) 9 987 d) 10 000 e) 2 890 e) 3 000 f) 1 234 512 f) 1 235 000 How to Round Whole Numbers to the Ten Thousands Place Example: Round 19 012 to the nearest ten thousands place | | | | | | | | | | 20 000 19 000 19 012 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the ten thousands place 19 012 How to Round Whole Numbers to the Ten Thousands Place Example: Round 19 012 to the nearest ten thousands place 2. Look to the right of the place you want to round to, Now look to the right of the ten thousands place 19 012 - If the digit is 5, 6, 7, 8 or 9 – the digit in the ten thousands place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the ten thousands place STAYS THE SAME The 1 in the ten thousands place goes up by one 19 012 20 000 How to Round Whole Numbers to the Ten Thousands Place Example: Round 19 012 to the nearest ten thousands place 3. Next, the digits to the right of the rounding place become zero. All the numbers on the right becomes zero 19 012 becomes 20 000 4. Anything to the left of the rounding place remains the same. So 19 012 rounded to the nearest ten thousands place is 20 000 How to Round Whole Numbers to the Ten Thousands Place Example: Round the following to the nearest ten thousands place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 __2 _65 234 2 343 45 678 65 723 199 789 1 222 222 0 70 230 2 340 45 680 65 720 199 790 1 222 220 Look to the value of the place to the right of the tens place Round the following numbers to the nearest ten thousands place. a) 45 653 a) 50 000 b) 567 809 b) 570 000 c) 12 342 565 c) 12 340 000 d) 456 789 d) 460 000 e) 112 343 e) 110 000 How to Round Whole Numbers to the Hundred Thousands Place Example: Round 145 to the nearest hundreds place | | | | | | | | | | 200 100 145 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the hundreds place 145 How to Round Whole Numbers to the Hundred Thousands Place Example: Round 145 to the nearest hundreds place 2. Look to the right of the place you want to round to, Now look to the right of the tens place 145 - If the digit is 5, 6, 7, 8 or 9 – the digit in the hundreds place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the hundreds place STAYS THE SAME The 1 in the hundreds place stays the same 145 100 How to Round Whole Numbers to the Hundred Thousands Place Example: Round 145 to the nearest hundreds place 3. Next, the digits to the right of the rounding place become zero. Now the 4 and 5 becomes zero 145 becomes 100 4. Anything to the left of the rounding place remains the same. So 145 rounded to the nearest hundreds place is 100 How to Round Whole Numbers to the Hundred Thousands Place Example: Round the following to the nearest hundred thousands place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 __2 _65 234 2 343 45 678 65 723 199 789 1 222 222 0 70 230 2 340 45 680 65 720 199 790 1 222 220 Look to the value of the place to the right of the tens place Round the following numbers to the nearest hundred thousands place. a) 455 555 a) 500 000 b) 156 789 b) 200 000 c) 12 345 876 c) 12 300 000 d) 12 000 542 e) 334 334 d) 12 000 000 e) 300 000 How to Round Whole Numbers to the Millions Place Example: Round 145 to the nearest hundreds place | | | | | | | | | | 200 100 145 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the hundreds place 145 How to Round Whole Numbers to the Millions Place Example: Round 145 to the nearest hundreds place 2. Look to the right of the place you want to round to, Now look to the right of the tens place 145 - If the digit is 5, 6, 7, 8 or 9 – the digit in the hundreds place goes UP by 1 - If the digit is 0, 1, 2, 3 or 4 – the digit in the hundreds place STAYS THE SAME The 1 in the hundreds place stays the same 145 100 How to Round Whole Numbers to the Millions Place Example: Round 145 to the nearest hundreds place 3. Next, the digits to the right of the rounding place become zero. Now the 4 and 5 becomes zero 145 becomes 100 4. Anything to the left of the rounding place remains the same. So 145 rounded to the nearest hundreds place is 100 How to Round Whole Numbers to the Millions Place Example: Round the following to the nearest millions place To Round: 2 65 234 2 343 45 678 65 723 199 789 1 222 222 __2 _65 234 2 343 45 678 65 723 199 789 1 222 222 0 70 230 2 340 45 680 65 720 199 790 1 222 220 Look to the value of the place to the right of the tens place Round the following numbers to the nearest millions place. a) 1 455 555 a) 1 000 000 b) 34 156 789 b) 34 000 000 c) 999 999 c) 1 000 000 d) 13 567 789 d) 14 000 000 e) 27 800 000 e) 28 000 000 How to Round Whole Numbers Example: Round 78 to the nearest tens place | | | | | | | | | | | | 78 80 70 Use a number line to help you visualize 1. Underline the place you want to round to. Here we want the tens place 78 Some Examples: 1. Round to the nearest 10 12 ____________ Or use a number line is 12 closer to 10 or to 20? Examples Because ... 3.1416 rounded to hundredths is 3.14 ... the next digit (1) is less than 5 1.2635 rounded to tenths is 1.3 ... the next digit (6) is 5 or more 1.2635 rounded to 3 decimal places is 1.264 ... the next digit (5) is 5 or more 134.9 rounded to tens is 130 ... the next digit (4) is less than 5 12,690 rounded to thousands is 13,000 ... the next digit (6) is 5 or more 1.239 rounded to units is 1 ... the next digit (2) is less than 5