What number comes next in the series: 2, 4, 6, 8, ?
Identify the missing number in the sequence: 1, 3, 5, ?, 9.
What is the next number in this pattern: 3, 6, 12, 24, ?
Which number should replace the question mark: 10, 20, 30, ?, 50?
Complete the sequence: 9, 7, 5, 3, ?
What number fits: 15, 18, 21, ?, 27?
Choose the missing square number: 1, 4, 9, ?, 25.
Which number comes next in: 7, 9, 8, 10, 9, ?
Find the next term: 2, 5, 8, 11, ?
What number should be placed in the blank: 100, 90, 80, ___, 60?