The purpose of this lesson is for students to add and subtract within 20 without composing or decomposing a ten.
In previous lessons, students learned the 1\(0 + n\) structure of teen numbers and considered the relationship between addition and subtraction. The purpose of this lesson is for students to use their understanding of the structure of teen numbers to add and subtract from a teen number, without composing or decomposing a ten (MP7). Students use methods they used in a previous section such as counting on, taking away, or relating addition and subtraction.
- Add and subtract single-digit numbers from teen numbers without composing or decomposing a ten.
- Restemos y sumemos hasta 20.
Teacher Reflection Questions
What connections did students make between the different methods shared? What questions did you ask to help make the connections more visible?