Study guide: Build and Read Numbers to One Thousand
Use hundreds, expanded form, comparisons, and skip-counting through 1000.
Ideas to explain in your own words
- Base ten builds a new place when ten units of the previous place are collected.
- Expanded form names the value of each digit.
- Hundreds decide first when comparing three-digit numbers.
- Skip-counting repeatedly adds the same amount.
Useful vocabulary
- hundred
- Ten tens or one hundred ones.
- expanded form
- A sum showing each place’s value.
Watch your reasoning
- A count of tens must be multiplied by ten to name the whole value.
- Three tens means thirty, not three.
- Do not choose a number only because its ones digit is larger.
- Crossing a place-value boundary does not change the counting rule.
A worked review example
Twelve tens represent 120 ones. Ten tens form one hundred and two tens remain, so the model is one hundred and two tens. Its numeral is 120. Twelve tens are not twelve ones; every original group was worth ten. Label every tens group with its value of ten. A count of tens must be multiplied by ten to name the whole value. Draw bundles of ten tens and mark their exchange for a hundred.
Make a practice plan
- Exchange Ten Tens for a Hundred: Nineteen tens make one hundred and nine tens: 190.
- Read Hundreds, Tens, and Ones in Expanded Form: Write 705 in expanded form. Expected: 700+5; the tens place is zero.
- Compare Three-Digit Numbers from the Left: Compare 608 and 680. Expected: 680 is greater because of its tens place.
- Continue a Skip-Count with Its Stated Step: Start at 650 and count by hundreds three times. Expected: 750,850,950.