Logical sequence, take your own time.

The operations of each step involve:

• flipping the first single and pair or two pairs of digits
• flipping the flipped single and pair or two pairs of digits
• adding the last pair of digits

See below:

$\LARGE \color{#D61F06}{\overrightarrow {34}} \space \color{#3D99F6} {\overrightarrow {82}} \space \color{#20A900} {\overline {69}} \\ \LARGE \color{#3D99F6} {\overleftarrow {28}} \space \color{#D61F06}{\overleftarrow {43}} \space \color{#20A900} {\overline {15}} \\ \LARGE \boxed {\color{#D61F06}{\overrightarrow {34}} \space \overrightarrow {\color{#3D99F6}{8} \color{#20A900}{2}} \space \color{#20A900} {\overline {6}}} \\ \LARGE \color{#3D99F6}{\overleftarrow {8}} \space \overleftarrow {\color{#D61F06}{4} \color{#20A900}{3}} \space \color{#20A900} {\overline {8}} \\ \LARGE \color{#D61F06}{\overrightarrow {4}} \space \overrightarrow {\color{#3D99F6}{8}} \space \color{#20A900} {\overline {11}} \\ \LARGE \color{#3D99F6}{\overleftarrow {8}} \space \overleftarrow {\color{#20A900}{4}} \space \color{#20A900} {\overline {2}} \\ \LARGE \color{#3D99F6}{\overrightarrow {8}} \space \color{#20A900} {\overline {6}}$

In the above sequence the digits in the number except the last two digits the order is reversed( Like digits 3482 of n.o 348269 is reversed and written as 2843) while the last two digits (which are here 69) are added (9+6=15) and the number formed is placed at the right end of the digit previously formed (284315) to obtain the next number . Applying above logic the missing number is

3482(1+5)=34826

1) separate the last 2 digits
2) reverse the rest of the digits
3) calculate the sum of the separated digits and return the sum as the last digit(s) of the reversed number.

2843 // 15
==> 3482 // 1+5
==> 34826

Enjoyed this one. Yumm!

Here's what I did (No Solution, just hint) ;)

-> Notice that every next number in series ends with a specific sum of last one.

-> Notice the numbers that repeat in the every number.

-> Think!

Use the previous number: 284315, to find the next number in the series.

1. Add the last pair of digits: 15 -> 6
2. Then reverse the rest of the number: 2843 -> 3482
3. Final add the two numbers together: 3482 & 15 -> 348215

The answer is 348215

Nice one :)