Skill: Round numbers to the nearest 100

To round a whole number to the nearest $100$:

1. Find the two multiples of $100$ that the number lies between.
2. Look at the tens and ones digits.
   • If they make $00$–$49$, round down.
   • If they make $50$–$99$, round up.
3. Write zeros in the tens and ones places. If rounding up causes a carry, increase the hundreds place.

Example: Round $2{,}950$ to the nearest $100$.

• The number lies between $2{,}900$ and $3{,}000$.
• Its tens-and-ones portion is $50$.
• Since $50$ means round up, choose $3{,}000$.

On a number line, $2{,}950$ is exactly halfway between $2{,}900$ and $3{,}000$, and halfway cases round up.

Therefore,

$$2{,}950 \approx 3{,}000$$

The tens and ones become zeros, and the $9$ in the hundreds place carries to make $3$ thousand.