2.7 Adding and Subtracting within 1,000
Unit Goals
- Students use place value understanding, the relationship between addition and subtraction, and properties of operations to add and subtract within 1,000.
Section A Goals
- Add and subtract numbers within 1,000 without composition or decomposition, and use strategies based on the relationship between addition and subtraction and the properties of operations.
Section B Goals
- Add numbers within 1,000 using strategies based on place value understanding, including composing a ten or hundred.
Section C Goals
- Subtract numbers within 1,000 using strategies based on place value understanding, including decomposing a ten or hundred.
Glossary Entries
- a third
One piece of a shape split into 3 pieces that are the same size.
A third of the rectangle is shaded.
- bar graphA way to show how many in each group or category using the length of rectangles.
- centimeter
A length unit in the metric measurement system. There are 100 centimeters in a meter.
- composeTo make a new unit from 10 of the next smallest unit. For example, compose a ten from 10 ones.
- dataInformation about the things or people in a group.
Example: If you have a box of colored pencils, then the lengths and colors of each of the pencils are data about the pencils in the box. - decomposeTo break a unit into 10 of the next smallest unit. For example, decompose a ten into 10 ones.
- expanded form
A specific way of writing a number as a sum of hundreds, tens, and ones.
Expanded form writes a number as a sum of the value of each digit. Example: 482 written in expanded form is \(400 + 80 + 2\) .
- faceA flat side of a solid shape.
- foot
A length unit in the U.S. customary measurement system.
There are 12 inches in a foot.
- hexagon
A shape with 6 sides and 6 corners.
- inch
A length unit in the U.S. customary measurement system.
There are 12 inches in a foot.
- line plotA way to show how many of each measurement using an x for each measurement.
- meter
A length unit in the metric measurement system.
There are 100 centimeters in a meter.
- number line
A diagram that represents numbers as lengths from 0 using equally spaced tick marks or points.
- pentagonA shape with 5 sides and 5 corners.
- picture graphA way to show how many in each group or category using pictures of the objects or symbols.
- quadrilateralA shape with 4 sides and 4 corners.
- thirds
The pieces created when a shape is split into 3 pieces that are the same size.
This circle is split into thirds.