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Place-Value Regrouping

Ten of any unit bundles into one of the next-higher place, and the reverse on the way down. Children first carry ones into tens and tens into hundreds, then extend the same rule to thousands, to multiplying by ten (which shifts every digit up one place), and finally to tenths regrouping into a whole. The single idea — units convert at a fixed exchange rate — is what every later number topic rests on.

grade 2–4 Measurement & dataBase-ten numbersFractionsOperations Look for a PatternCreate a Physical Representation

Progression (7)

g4 1. Carry ten units to the next place Base-ten numbers · foundational
g4 2. Ten hundreds make one thousand Base-ten numbersMeasurement & data · foundational
g3 3. Ten in a place carries forward Base-ten numbers · core
g4 4. Ten tenths make one whole Fractions · core
g4 5. Ten of a unit carries to the next place Base-ten numbers · core
g4 6. Skip-count by the changing place value Base-ten numbersOperations · advanced
g4 7. Times ten adds one place Base-ten numbers · advanced

Bridges to competition (3)

Reasoning problems that extend this idea toward competition:

Add and subtract by splitting numbers Other → Arithmetic Expression Decomposition
Sum of all numbers from digit cards Counting → Casework by Position / Vertex Type
Read positional rod numerals Pattern & rule → Arithmetic Expression Decomposition

Leads to competition types: Arithmetic Expression DecompositionCasework by Position / Vertex Type