Adding & Subtracting with Place Value

Adding & Subtracting with Place Value

Grade 2 Mathematics Learning with Bryony Using tens and ones to solve problems

I Can Statements

I can use place value to add and subtract two 2-digit numbers I can use properties of operations to solve problems I can relate addition and subtraction to check my work I can write the correct answer for 4 out of 5 problems

Place Value Warm-Up

Look at the number 47 How many tens? How many ones? Use your base-ten blocks to show this number Let's practice with 23, 56, and 81

Three Strategies for Success

Decompose by Place Value: Break numbers into tens and ones Make Ten (Compensation): Adjust numbers to make calculations easier Inverse Relationship: Use addition to check subtraction and vice versa

Strategy 1: Decompose by Place Value

Your Turn to Try!

Problem: 54 - 21 First, break each number into tens and ones What strategy will you use? Explain your thinking out loud

Checking Our Work

{"left":"Addition Check: If 25 + 34 = 59, then 59 - 34 should equal 25\nSubtraction Check: If 67 - 23 = 44, then 44 + 23 should equal 67","right":"This helps us know if our answer is correct\nAddition and subtraction are opposite operations"}

Independent Practice & Assessment

Complete 5 problems using your favorite strategies Show your work with tens and ones Check at least 2 answers using inverse operations Goal: Get 4 out of 5 correct!