Tap any rule to see why the threshold sits where it does.
Write the arithmetic out even when it is trivial. That is the habit that protects the child when the numbers are larger.
Adequacy of feeding is judged by output and growth, not by the bottle: six or more wet nappies daily after the first week, appropriate stooling, and return to birth weight by 10 to 14 days.
Immunisation schedules are set nationally and differ between countries. Always administer according to the current national schedule rather than from memory; what is drilled here are the principles that hold everywhere.