Functional Skills
Mathematics
Level 1
Learning Resource 4
Rounding/Estimation
N1/L1.8
N1/L1.9
ROUNDING/ESTIMATION
LEVEL 1
Excellence in skills development
4
Contents
Rounding to the nearest 10, 100, 1000, million
N1/L1.8
Page
Using Estimation to Check Results
N1/L1.9
Pages 4 – 5
©West Nottinghamshire College
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2
ROUNDING/ESTIMATION
LEVEL 1
N1/L1.8
Excellence in skills development
Information
4
Rounding to the nearest 10, 100, 1000, million
When rounding, the number comes between two possible answers. Choose the number it
is nearest to. If the number is in the middle, then round up. Rounding numbers to the
nearest 10 and 100 are easier to work with than number ending in 59 or 74.
Examples
Round 36 to the nearest ten.
It is nearer to 40.
36 is between 30 and 40.
Answer 40
Round 457 to the nearest hundred.
It is nearer to 500.
457 is between 400 and 500
Answer 500
Round 2845 to nearest thousand.
It is nearer to 3000.
2845 is between 2000 and 3000
Answer 3000
Exercise 1
1)
Round the following numbers to the nearest ten.
a)
2)
19
c)
93
d)
172
e)
345
75
b)
124
c)
358
d)
605
e)
877
d)
8950
e)
9606
Round the following to the nearest thousand.
a)
4)
b)
Round the following to the nearest hundred.
a)
3)
8
595
b)
1052
c)
7499
Round the following to the nearest million.
a)
700,000
b)
1,482,041
c)
7,941,000
d)
2,500,000
©West Nottinghamshire College
3
ROUNDING/ESTIMATION
LEVEL 1
N1/L1.9
Excellence in skills development
Information
4
Using Estimation to Check Results
Estimation is sometimes used to give an approximate answer to a calculation. This is
useful when you need to do a rough estimate or when a sensible approximation figure
would be adequate. When estimating, you need to round to an appropriate number. This
may be to the nearest 5, 10 or 100.
Examples
By using rounding and estimation, you can judge whether your answers are sensible.
You buy a round of 6 drinks which cost £2.34 each.
Rounded to the nearest 50p, the calculation becomes 6 x £2.50 = £15.
So you know to expect over £5 in change from a £20 note.
You buy 4 oranges at 23p each.
Rounded to the nearest 5p, the calculation becomes 4 x 25p = £1.
So you know that £1 is enough to buy the oranges.
You have calculated that you need 78 metres of wood to make a fence. The wood costs
87p per metre.
Rounded to the nearest 10, the calculation becomes 80 x 90p = 7200 = £72.00.
You should have change from £72.
©West Nottinghamshire College
4
ROUNDING/ESTIMATION
LEVEL 1
N1/L1.9
Excellence in skills development
Exercise 2
1)
Using Estimation to Check Results
Complete the following table:
e.g.
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
2)
4
Question
212 × 91
111 × 222
875 × 98
301 × 709
65 × 1009
41 × 92
82 × 533
589 × 216
71 × 79
391 × 68
902 × 14
88 × 3228
243 × 639
Estimate
200 × 100 = 20000
Actual
212 × 91 = 19292
There are 65 people in the factory. Each person drinks 1 fizzy drink each day for
20 –21 days per month. I have ordered 1400 drinks for next month. Have I
calculated correctly?
Yes / No
3)
Jo sells 402 bunches of flowers each week. She has calculated that she sells
200,000 bunches in a year. If she works 48 weeks per year, is her calculation likely
to be correct?
Yes / No
4)
Terry buys 3 items costing £48 each. The shop charges him £198. Has the shop
charged Terry too much?
Yes / No
5)
Phil is starting a new job soon and needs to buy 4 shirts. The price of each shirt is
£19.50. Phil calculates he can buy 5 for £100. Is he correct?
Yes / No
©West Nottinghamshire College
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