how to find passive perception

For Christmas my kiddo got the D&D Starter Set and we've been going though it and the full rules we downloaded online. I'm having a hard time figuring out how the example listed in the rules ge…

Passive checks are calculated like so:

10 + all modifiers that normally apply to the check

If the character has advantage on the check, add 5. For disadvantage, subtract 5.

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The "all modifiers that normally apply to the check" are the numbers that the player would add to the 20-sided die if they were rolling the ability check instead of using the passive check. These modifiers include:

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the ability score modifier.
the proficiency bonus, if the character is proficient in the check.
any miscellaneous bonuses granted by racial traits, class features, feats, spells, etc.

Examples, in increasing complexity

A 1st-level character with Wisdom of 10 and no proficiency in Perception (the pre-generated character example):

the bonus to Perception is wisdom modifier = 0
the Passive Perception is 10 + Perception bonus = 10 + 0 = 10.

A 1st-level character with a Wisdom of 15 and proficiency in Perception (the PHB example):

the bonus to Perception checks is wisdom modifier + proficiency bonus = 2 + 2 = 4
the Passive Perception is 10 + Perception bonus = 10 + 4 = 14.

A 1st-level character with a Wisdom of 13 and proficiency in Perception who is in surrounded by patchy fog¹:

the bonus to Perception checks is wisdom modifier + proficiency bonus = 1 + 2 = 3
the Passive Perception is 10 + Perception bonus - disadvantage = updating = 8.

A 5th-level Bard with a Wisdom of 13, no proficiency in Perception, and the Jack of All Trades² feature:

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the bonus to Perception is wisdom modifier + Jack of All Trades = 1 + 1 = 2
the Passive Perception is 10 + Perception bonus = 10 + 2 = 12.

A 5th-level character with a Wisdom of 18, proficiency in Perception, and the Observant³ feat:

the bonus to Perception is wisdom modifier + proficiency bonus = 4 + 3 = 7
the Passive Perception is 10 + Perception bonus + Observant = updating = 22.

The following are two cropped images of the pre-generated halfling rogue and the pre-generated human fighter respectively, which show similar calculations. Note that the grey dot indicates proficiency. How to calculate passive perception?

Vision and Light. In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.
Jack of All of Trades. Starting at 2nd level, you can add half your proficiency bonus, rounded down, to any ability check you make that doesn't already include your proficiency bonus.
Observant. You have a +5 bonus to your passive Wisdom (Perception) and passive Intelligence (Investigation) scores.

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