Maths. Saw this on our video? Tap the answer your child chose to check it, then open the worked answer to see why the tempting wrong options catch so many children out.
Question 8Aim for about 60 seconds
If n = 4, what is the value of 4n²?
Show the worked answer
Answer: C, 64
How to work it out
Square first: n² = 4 × 4 = 16.
Then multiply by 4: 4 × 16 = 64.
Why the other options are wrong
A (32): This treats n² as n × 2; squared means 4 × 4.
B (256): This squares 4n, which is 16; in 4n² only the n is squared.
D (20): This adds 4 to 16; 4n² means 4 times n².
E (16): This is 4 × 4; the n must be squared first.
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Solving equations, substitution and “think of a number”.
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