Rounding up Rounding Numbers Rounding down Start a

Rounding up Rounding Numbers Rounding down Start a mind map with these areas and branches.

Rounding Numbers Rounding a number is when you take a number and "bump it up" $4. 99 rounds up to $5 or "bump it down" to a nearby and "cleaner" number. $9. 02 rounds down to $9

Rounding Numbers A number can be rounded to any place value you want. Car prices: $13, 473. 99 can round to Ones place: $13, 474 Tens place: $13, 470 Hundreds place: $13, 500 Thousands place: $13, 000

Rounding Numbers Rounding means reducing the digits in a number while trying to keep its value similar. Calculator answers: 5. 284729 can round to Two digits: 5. 3 Three digits: 5. 28 Four digits: 5. 285 One digit: 5

How to Round Numbers – Rounding Down Find place you want to round to Draw your “rounding line” Look one place to the right Is the digit less than 5? Rounding Down: leave digit rounding the same…. if the next digit is less than 5…substituting zeroes for digits dropped up to the decimal. Example: Round 74 to the nearest 10 keep • • • 74 <5 Answer: 70 (74 gets "rounded down")

How to Round Numbers – Rounding up keep Find place you want to round to Draw your “rounding line” Look one place to the right Is the digit 5 or more than 5? Rounding up: increase the digit you are keeping by 1… if the next digit is 5 or more • (substitute zeroes for any digits dropped further to the right up to the decimal. ) • • • Example: Round 86 to the nearest 10 86 >5 Answer: 90 (86 gets "rounded up")

Example 1 • Round the atomic mass of carbon to 3 digits. • (look on periodic chart for number below the symbol) • Given -- 12. 011 amu • Rounded – 12. 0 amu

Example 2 Round the atomic mass of yttrium to 3 digits. Given -- 88. 906 amu Rounded – 88. 9 amu Now, round the same starting number to 4 digits. • Given -- 88. 906 amu • Rounded – 88. 91 amu • •

Example 3 • Round the atomic mass of oxygen to 3 digits. • Given -- 15. 999 amu • Rounded – 16. 0 amu