Science and logic reasoning: What is the missing number: 2, 6, 12, 20, 30, ___?
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The terms follow n(n + 1): 1×2, 2×3, 3×4, and so on.
The next term is 6×7 = 42.
Practice AKU Science and Mathematics Reasoning questions with answers and explanations.
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The terms follow n(n + 1): 1×2, 2×3, 3×4, and so on.
The next term is 6×7 = 42.
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Each term increases by 3.
Adding 3 to 12 gives 15.
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Each term is double the previous term.
Therefore, 16 × 2 = 32.
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The square root is the number whose square equals 196.
Since 14 × 14 = 196, the answer is 14.
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The cube root is the number that gives 729 when cubed.
Since 9³ = 729, the answer is 9.
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The sequence increases by 3 each time.
Adding 3 to 11 gives 14.
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The sum of the first n natural numbers is n(n + 1)/2.
For n = 10, the sum is 10 × 11 ÷ 2 = 55.
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The sum of the first n odd numbers equals n².
For n = 8, the sum is 8² = 64.
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The least common multiple of 3 and 4 is 12.
A number divisible by both must therefore be divisible by 12.
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The units digits of powers of 7 cycle as 7, 9, 3, 1.
The fourth power therefore ends in 1.
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The greatest common divisor of 18 and 24 is 6.
Dividing both terms by 6 gives 3/4.
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Convert 2/3 to sixths: 2/3 = 4/6.
Then 4/6 + 1/6 = 5/6.