Accura and ltlleasurin

Accura
and ltlleasurin
No rnalter how accuralelg Uou rneasure sornething, Uou're alwags going to be a teensg bil out.
It usuallg doesn't rnatter in the slighlesl for real-life, bul it does for gour Maths gxarn.
1)
str
and
f,ffiffirstr
bounds of a &$mm$ffitrssarent
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The sirnple rule is lhis:
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A room is given as being'9 m long to the nearesl METRE'- its aclual lengfh could
i.e. HALF A METRE either side of 9 rn.
be angthing frorn 8.5 rn up lo 9.5 m
$o 8.5m and 9.5m are the lower and'upper bounds.
2) lf il was given as '9.4 rn, lo lhe nearesl v;! ]r',lhen it could be angthing from
i.e. O.l rn eilher side of 9.4 m.
9.3 m up lo 9.5 m (9.4 m + O.l m)
So 9.3 rn and 9.5 m are lhe lower and upper bounds.
3) lf a lenglh is gven as 2.4 rn lo ihe nearest OL-ng, lhe rounded unit is O.l m so lhe
real value could be angihing up lo 2.4 m t O.O5 m givin! answers oI 2.45 m and
2.35 m for lhe upper and lower bounds.
4l
lhe actual figure
'A school has 460 pupils to 2 Sig Frg' (i.e. to the nearest lO)
(Whg isn't it 465?l
could be angthing from 455 up to 464.
So 455 and 464 are lhe upper and lower bounds.
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2t filaximum and lvlinimum Values for Calculations
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When a calculalion is done using rounded-off values lhere will be a DISCREPANCY
between +he CALCULATED VALUE and the ACTUAL VALUE:
t
DGMPLE: A floor is rneasured as being 5.3 m x 4.2 m to lhe nearesl lO crn.
Calculate lhe minimum and maxirnurn values for lhe area and perimeter.
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lhis
Boundless enthusiasm
hope yours
isnt weartng oat yet...
L""rn all ihe bils and bobs on
iuin over and see how much gou
Trg lhese loo:
""ni"rernber.
A gacht is described as 17 melres long lo the nearesl O.l m. What is rhe longest and shorlesi it could be?
Z) * and g are measured as 2.32 m and O.45 rn to the nearesl O.Ol m.
Find lhe upper and lower bounds of x and g.
page then
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Section Two
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More Numbers