Which number is missing from the sequence?
114, 109, 104, ____, 94, 89.

The correct answer is: 99

The given sequence is 114, 109, 104, __, 94, 89
We will subtract second term from first term.
We will see if we get a constant that we can use to write the complete pattern.
114 – 109 = 5
Now, we will subtract this constant from second term to see if we get the third term. The number sequence is decreasing. So, we need to subtract the constant.
109 – 5 = 104
This matches the third term of given sequence. So, we will continue the subtraction to see if we get last two terms right too.
104 – 5 = 99
99 – 5 = 94
94 – 5 = 89
All the terms matches the given pattern.
The complete sequence will be 114, 109, 104, 99, 94, 89
Therefore, the missing term is 99.

For such questions, we should know the basic operations. When the rule used to write the pattern is not mentioned, we have to use all four operations to check the pattern. The operations are addition, subtraction, division, and multiplication.