Review

Key Ideas

Comparisons produce booleans.
if runs a block when its condition is true.
elif checks another condition.
else handles the remaining case.
Indentation defines the block.
for repeats over a sequence or range.
range(stop) starts at 0 and stops before stop.
while repeats while a condition remains true.
A running total accumulates values across loop iterations.
Off-by-one errors come from boundary mistakes.

Key Syntax

Syntax	Meaning
`score >= 5`	comparison
`if condition:`	run a block when true
`elif condition:`	check another condition
`else:`	fallback branch
`for item in items:`	repeat once per item
`range(5)`	`0, 1, 2, 3, 4`
`while condition:`	repeat while true
`total = total + value`	update a running total

Common Mistakes

Mistake	Fix
Using `=` when comparing	use `==`
Putting broad `if` branches before specific ones	check specific cases first
Forgetting indentation	indent the branch or loop body
Expecting `range(5)` to include `5`	remember the stop value is excluded
Forgetting to update a `while` loop condition	update inside the loop
Resetting a total inside the loop	initialize before the loop

Checklist

You are ready to move on if you can:

predict a comparison result
trace an if / elif / else statement
write a for loop over a small list
explain what range(4) produces
trace a while loop with a changing counter
compute a running total
identify an off-by-one boundary

If You Feel Lost

Trace by hand. Make a small table with the loop variable, condition, and any changing values. Programs become easier when their state is visible.