Title: Rounding Decimal Numbers
1Rounding Decimal Numbers
- Sometimes close enough is good enough!
2Molly has 16 in her pocket
- She buys
- 3 hotdogs _at_ 1.89 each
- 3 milkshakes _at_ 2.19 each
- 3 Large French fries _at_ 1.79 each
Does she have enough money?
3Gas costs 1.79 per gallon
Im running on empty and I have a 20 gallon tank
on my truck About how much will it cost to
fill up?
4You have one hour to take a 50 question test.
About how much time can you spend on each
question?
Close enough is good enough!
5The rounding poem
Find your number Look right next door 4 or less,
just ignore 5 or more add one more!
6Rounding Whole Numbers
Round 474 to the closest hundred.
474
Five or more, add one more.
Four or less, just ignore.
474 Rounded to the hundreds becomes 500.
7Rounding Whole Numbers
Round 474 to the closest 10s
474
Four or less, just ignore.
474 Rounded to the tens becomes 470.
8Try to round off these numbers
- 4,215 (to nearest hundred)
- 394 (to nearest ten)
- 27 (to nearest ten)
- 127,591 (to nearest thousand)
- 638 (to nearest hundred)
9What about decimal numbers ?
The same rules (and poem) apply!
Round 4.167 to the closest hundredths.
4.167
Find your number.
Look right next door.
Answer 4.17
10Remember
If you are asked to round to the nearest
tenth.your answer stops at the tenth place!
Example Round 42.73 to the closest tenth would
be 42.7
11Special Case!Rounding a 9
Round 2.197 to the closes hundredths
Since there is a 9 in the hundredths place
consider the tenth and hundredths together 19
do you leave it at 19 or move it to 20?
12Round 4.95 to the closest tenth
Since there is a 9 in the tenth spot consider
the ones and tenths together should you leave
it at 49 or move it to 50?
4.95 rounded to the nearest tenth is 5.0
13Try these
Round to hundredths
Round to tenths
4.56
4.6
18.784
18.78
5.32
5.3
9.46
9.456
10.00
0.98
1.0
9.997