Section 1
Decomposing Place Value Units
Property
Decomposing a place value unit means trading it for 10 of the next smaller unit. This is done when you don't have enough in a place value to subtract.
In this Grade 4 enVision Mathematics lesson from Chapter 2, students learn how to subtract multi-digit whole numbers using the standard algorithm, including regrouping across the ones, tens, and hundreds places. The lesson connects place-value concepts to written subtraction procedures, helping students work efficiently with problems like 358 − 172. Students also practice estimating differences to check the reasonableness of their answers.
Section 1
Decomposing Place Value Units
Decomposing a place value unit means trading it for 10 of the next smaller unit. This is done when you don't have enough in a place value to subtract.
Section 2
Standard Subtraction with Single Regrouping
When subtracting vertically, if a digit in the top number (minuend) is smaller than the digit below it (subtrahend), you must regroup. To regroup, you decompose 1 from the next higher place value to the left and add 10 to the current place value. For example, 1 hundred becomes 10 tens, or 1 ten becomes 10 ones.
Expand to review the lesson summary and core properties.
Section 1
Decomposing Place Value Units
Decomposing a place value unit means trading it for 10 of the next smaller unit. This is done when you don't have enough in a place value to subtract.
Section 2
Standard Subtraction with Single Regrouping
When subtracting vertically, if a digit in the top number (minuend) is smaller than the digit below it (subtrahend), you must regroup. To regroup, you decompose 1 from the next higher place value to the left and add 10 to the current place value. For example, 1 hundred becomes 10 tens, or 1 ten becomes 10 ones.