Fast, Free & Accurate Online IQ Test

This question assesses your fluid reasoning and pattern recognition skills by requiring you to identify the mathematical relationship governing the sequence and apply it to find the missing number. The given sequence is:

• 1
• 8
• 27
• ?
• 125
• 216

Observing the sequence, the numbers increase rapidly, suggesting that they may be related to powers or exponents. Specifically, these numbers correspond to the cubes of consecutive positive integers. Let's verify this:

• 1³ = 1 * 1 * 1 = 1
• 2³ = 2 * 2 * 2 = 8
• 3³ = 3 * 3 * 3 = 27
• 4³ = 4 * 4 * 4 = 64
• 5³ = 5 * 5 * 5 = 125
• 6³ = 6 * 6 * 6 = 216

Matching these results to the sequence:

• 1 corresponds to 1³ = 1
• 8 corresponds to 2³ = 8
• 27 corresponds to 3³ = 27
• ? corresponds to 4³ = 64
• 125 corresponds to 5³ = 125
• 216 corresponds to 6³ = 216

Therefore, the missing number is 4³ = 64.

This problem tests your ability to recognize patterns involving exponents and apply mathematical concepts to solve problems. Identifying that the sequence consists of cubes of consecutive integers demonstrates strong fluid reasoning, as it requires abstract thinking and the ability to manipulate numerical information mentally.

Similar Examples:

• A sequence of square numbers: 1, 4, 9, 16, ?, 36 (missing number is 25, since 5² = 25).
• A sequence involving factorials: 1, 2, 6, 24, ?, 720 (missing number is 120, since 5! = 120).
• A sequence of prime numbers: 2, 3, 5, 7, 11, ? (missing number is 13).

These types of questions evaluate your ability to identify underlying mathematical relationships and apply them to find missing elements, which is a key aspect of fluid intelligence.

Answer: 64