To solve this sequence, we need to identify a pattern or rule that applies to the numbers. Let's first examine the given sequence:

99, 42, 899, __, 50, 16, 16, 19, ?

Step-by-Step Analysis:

1. First Difference Approach: Observing the numbers, there doesn't seem to be a simple arithmetic or geometric progression. Let's analyze the differences:

   • Difference between 99 and 42: $99 - 42 = 57$
   • Difference between 42 and 899: $899 - 42 = 857$
   • Difference between 899 and the missing number is unknown.
   • Difference between the missing number and 50 is unknown.

2. Second Difference Approach: Let's consider other possible patterns. We can observe two sequences:

   • The sequence could potentially be split into two separate sequences:
     • First sequence: 99, 899, (missing), 16
     • Second sequence: 42, 50, 16, 19

   Now, let's identify the potential pattern for each split sequence.

3. Potential Patterns:

   • First Sequence: $99, 899, \text{?}, 16$

     • It seems that numbers are alternating dramatically.
     • We might assume some large multiplicative or additive jump from 99 to 899.

   • Second Sequence: $42, 50, 16, 19$

     • Here, there might be a simpler pattern:
       • $42 + 8 = 50$
       • $50 - 34 = 16$
       • $16 + 3 = 19$

     This shows an alternating addition and subtraction pattern with a decrease in the numbers.

Conclusion:

If the second sequence is alternating with smaller increments, the missing number might logically follow this irregular pattern.

If we assume the first sequence is also an alternating irregular sequence, then:

• The first sequence may involve a subtractive jump, potentially making the missing number (e.g., between 899 and 16, quite large and a drop of 883).

Missing Number:

Thus, the missing number may not follow a clear pattern without further context, but considering sequence continuity and alternating patterns:

1. The missing number between 899 and 50 would be some sharp drop.

Would you like me to explore alternate pattern options for this solution or a related question on identifying missing sequences based on differing patterns?