Round this number
to the nearest tenth (1 dp)
Step 1 — Find the place you're keeping
Step 2 — Look at the very next digit
Step 3 — 5 or more rounds up, less than 5 rounds down
Step 4 — Write the answer
The decider is the first digit you're throwing away. If it's 5 or more, bump the kept digit up by one; if it's less than 5, leave it alone. Everything after the decider just disappears.