Q.1
When x is an integer, 2x - 1 will always be an odd number, regardless of the value of x; what is the proof?
  • 2 - 1 = an odd number
  • 2 + 1 = an odd number
  • 2x = an even number and one less will be an odd number
  • Any term with a - sign in it produces an odd number
Q.2
You can never work out the exact area of a circle; what is the proof?
  • Pi is required to work it out and its exact value is unknown
  • The area of a circle is infinite
  • The theorem of Pythagoras doesn't work with circles
  • There are no formulae for circular areas
Q.3
345,345,345,345 when doubled will be an even number; what is the proof?
  • All numbers over 1,000 are even numbers
  • Doubling any number results in an even number
  • Each 4 has a 3 on one side and a 5 on the other side
  • Repeated sequences result in even numbers
Q.4
Simon says that if a number is not prime it will always have an even number of factors. Which of these statements proves that he is wrong?
  • All prime numbers have two factors
  • Many numbers have 3 as a factor
  • Any square number has an odd number of factors
  • That's just the way it is
Q.5
To prove a result is the same as to ....... the result?
  • Debate
  • Guess
  • Justify
  • Question
Q.6
Sam says that the sum of two prime numbers is always even. How could you prove if he is right or wrong?
  • Check a few sums
  • Find a sum which is odd
  • Do some reverse calculations
  • Find a sum which is even
Q.7
With the exception of the number 2, all prime numbers are odd numbers; what is the proof?
  • 2 is a factor in all even numbers
  • 2 is the next number after 1
  • 4 divided by 2 gives a whole number
  • Exponents of 2 always give an even number
Q.8
Which of the following is a correct definition of 'proof'?
  • An assumption
  • An estimation
  • An opinion
  • Evidence that establishes something is true
Q.9
If one of the angles in a triangle is 90° the other two angles must add up to 90°. What fact is used to prove the truth of this statement?
  • Two sides of the triangle are equal
  • The other two angles must both be 45°
  • The angles of any triangle add up to 180°
  • All triangles have three angles
Q.10
The word horse has 5 letters beginning with the letter H and so does the name Henry which proves Henry is a horse. Why is this statement false?
  • The similarity in spelling is accidental
  • No one would call a horse Henry
  • Henry's name starts with a capital letter
  • You can't mix humans with animals
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