Lesson 2

Sumemos y restemos con decenas y centenas

Lesson Purpose

The purpose of this lesson is for students to add and subtract multiples of 10 and 100 within 1,000.

Lesson Narrative

In grade 1, students added and subtracted multiples of 10 within 100. In a previous unit, students represented three-digit numbers with base-ten blocks, drawings, and words. Students used equations to represent three-digit numbers as sums of the value of hundreds, tens, and ones using the number and name of each unit (235 = 2 hundreds + 3 tens + 5 ones) and using expanded form ($$235 = 200 + 30 + 5$$).

In this lesson, students add and subtract three-digit numbers and multiples of 10 and 100 using what they know about tens and hundreds. Students compare representations such as base-ten blocks, base-ten diagrams, and equations to understand that when adding or subtracting multiples of 10, the tens place changes and when adding or subtracting multiples of 100 the hundreds place changes (MP7, MP8).

• Representation
• MLR7

Learning Goals

Teacher Facing

• Add and subtract multiples of 10 or 100 to/from a three-digit number.

Student Facing

• Sumemos y restemos decenas o centenas.

Required Materials

Materials to Gather

Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

Teacher Reflection Questions

In previous lessons, students represented three-digit numbers as sums of hundreds, tens, and ones. How does that understanding support students as they add and subtract multiples of 10 and 100?

Suggested Centers

• Jump the Line (2–5), Stage 1: Add and Subtract within 100 (Supporting)
• Number Line Scoot (2–3), Stage 1: Twos, Fives, and Tens (Supporting)