Download Examples of children`s reasoning from KS2 SATs papers

Session 3 Sheet 5 Analysing children’s reasoning from KS2 SATs papers 2007
Reasoning about triangles:
Q: Jamie draws a triangle. He says, ‘Two of the three angles in my triangle are
obtuse’. Explain why Jamie cannot be correct.
Because it is impossible to get all three triangles obtuse.
Because all angles in a triangle add up to 180 degrees and there are always three
angles in a triangle. An obtuse angle is an angle that measures over 90 degrees and
90 is ½ of 180. So therefore say 91 +91 already is over 180. So there can be 3 acute
angles or 1 obtuse angle and 2 acute angles but never 2 obtuse angles.
Because they cannot be because it would not add up to 180 degrees.
All the angles in a triangle add up to 180 so you couldn’t make a triangle with two
obtuse angles.
All the angles in a triangle have to add up to 180. An obtuse angle is above 90. But
three numbers greater than 90 cannot add up to 180.
Because if there over 90 it won’t be able to join up.
Because a triangle only has 3 sides and there is not a triangle that has 2 out of 3
obtuse angles
Because you cannot have a triangle with 2 obtuse angles. E.g. This is a shape with 2
obtuse angles but 4 sides
Reasoning about multiples
Q: Explain why a number that ends in ‘3’ cannot be a multiple of 4
3 doesn’t go into 4
Because in the 4 or 6 times tables it never ends in 3.
Because if you divide anything by 4 it will end in an even number.
Multiples of four never end in a three.
Because all multiples of 4 end in 4,8,2,6,0 but not in 3. This means that no number
that ends in a 3 is a multiple of 4.
Because 3 is an odd number and 4 isn’t odd
Because its and odd number
Because 3 is only one less than 4 and to be a multiple of 4 it has to be 4 more than a
number in the 4 x table