Ocean depths

Ocean depths

Pencil and paper
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This task is about significant figures.
deep sea exploration
 
The deepest parts of the ocean floor are in the Pacific Ocean. These are given particular names, for example Challenger Depth. Answer these questions about each of these depths.
 
a)
The deepest part of the ocean floor is Challenger Depth which is 11,022 metres.
 
How many significant figures are there in this number? __________
 
b) Round each of these depths to 2 significant figures (2 s.f.).
 
 
i)   Johnson Depth is 10,497 metres = ____________________ metres (2 s.f.)
 
ii)  Planet Earth Depth is 9,140 metres =   ____________________ metres (2 s.f.)
 
iii) Vityaz Depth is 10,542 metres =   ____________________ metres (2 s.f.)
 
c) Round each of these depths to 3 significant figures (3 s.f.).
 
 
i)   Nero Depth is 9,637 metres  =   ____________________ metres (3 s.f.)
 
ii)  Horizon Depth is 10 882 metres  =   ____________________ metres (3 s.f.)
Task administration: 
This task is completed with pencil and paper only.
Copyright: 
deep sea exploration
Image: US National Oceanic and Atmospheric Administration (Public domain).
Level:
5
Curriculum info: 
Maths, Number and Algebra, Number Knowledge
Keywords: 
significant figures, place value
Description of task: 
Students identify significant figures in given numbers, and round numbers to a given number of significant figures.
Answers/responses: 
 

Y10 (09/1999)
a)   5 moderate
b) i)
ii)
iii)		 10,000
9,100
11,000		 moderate
moderate
difficult
c) i)
ii)		 9,640
10,900		 difficult
difficult
Diagnostic and formative information: 
    Common error Likely reason
a) 4 Treats 0 that is imbedded in the number as non-significant.
b) iii)
c) i)
    ii)		 10,000
9,630
10,800		 Rounds down rather than up to nearest number with specified number of significant figures.
b) i)
    ii)
    iii)		 10
91
11		 Quotes first 2 digits but forgets to put zeros on the end of the number.
c) i)
    ii)		 963, 964
108, 109		 Quotes first 3 digits and forgets to put zeros on the end of the number.
b) i)
    ii)
    iii)		 10.4, 10.49, 10.5, 10.97
91.4
10.5, 10.55, 10.542		 2 digits to the left of decimal point.
c) i)
    ii)		 9 63.7
108.8, 108.82		 3 digits to the left of decimal point.