Exchange Ten Tens for a Hundred

Supplied materials

• Paper and a pencil; drawing and spoken explanations are welcome. An adult may read directions and options aloud.
• Supplied worked-case record: Twelve tens represent 120 ones.
• All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

Base ten builds a new place when ten units of the previous place are collected. Ten ones make one ten and ten tens make one hundred. An exchange preserves the amount while making the model easier to read. More than nine tens can be regrouped.

Group the supplied tens into sets of ten tens. Rename each full set as a hundred, leaving any extra tens separate. Convert the model to a numeral and check its total number of ones.

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.

1. Draw bundles of ten tens and mark their exchange for a hundred.
2. Follow the worked example. Point to each number or shape feature and say what it tells you.
3. Group the supplied tens into sets of ten tens.
4. Try the question and then the three practice questions. Check your answers and explain any change you make.

Check your reasoning

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Take it further

Nineteen tens make one hundred and nine tens: 190.

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