Mastering Addition and Subtraction of Tens: A Comprehensive Lesson Plan
This lesson plan focuses on teaching students how to add and subtract multiples of ten using various strategies. Students will engage with place value materials like charts and personal whiteboards to reinforce their understanding of counting up and down. Activities include visualizing numbers with disks, performing mental math, and solving story problems. The lesson emphasizes different techniques, including the Say Ten and Arrow Way methods, to ensure students grasp conceptual understanding while building confidence in their mathematical skills.
Mastering Addition and Subtraction of Tens: A Comprehensive Lesson Plan
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Presentation Transcript
Module 4 Lesson 2
Objective • Add and subtract multiples of 10 including counting on to subtract.
Place Value Materials: Place value charts, personal white boards • Show 1 ten and 3 ones in number disks. Write the number below it. • Say the number in unit form. • 1 ten 3 ones. • Say the number in standard form. • 13.
Place Value Continued • Add 2 tens to your chart. How many tens do you have now? • What is 20 more than 13? • Add 3 tens to 33. How many tens do you have now? • 6 tens. • What is 30 more than 33? • Say the number in unit form. • 6 tens 3 ones. • Now subtract 4 tens from 63. What is 40 less than 63? • 23.
How many more tens? • If I say 34 ─ 24, you say 10. To say it in a sentence you say 34 is 10 more than 24. Ready? • 64 – 44. • Say it in a sentence. • 64 is 20 more than 44. 68 – 38 59 – 49 47 – 17 85 – 45 99 – 19
Concept Development • Yesterday we added and subtracted 1 ten. Today, let’s add 2 tens, then 3 tens, and more! • How many do you see? • The Say Ten way? • What would have if I were to add 2 more tens? Turn and talk. • What is 34 + 20? The say ten way.
Concept Development Continued The Arrow Way • If I asked you to add 3 tens to 26, how could you solve that? • Let’s show that on the board using both simplifying strategies, the arrow way and number bonds. I know many of you can just do mental math! • I can write adding 3 tens the arrow way, as we did yesterday. • I can also break apart the tens and ones with a number bond, add the tens and then add the ones. • No matter which way I write it, when I add tens to a number, the ones stay the same! 26 +10 36 +10 46 +10 56 26 56 +30 Number Bonds 26 + 30 = 56 20 + 30 = 56 50 + 6 = 56 20 6 Mental Math 26 + 30 = 56
Concept Development Continued • Now it’s your turn. On your personal white board, solve 18 + 20. Show your board when you have an answer. • Let’s try a few others: 25 + 50 38 + 40 40 + 27
Concept Development Continued • Ok, now subtract 3 tens from 56. Take a moment and work on your personal board to solve 56 – 30.
Concept Development Continued • We have an extra simplifying strategy when we are subtracting. We can count up from the part we know. • What is the whole? • 56. • What is the part we know? • 30. • How could we show the missing part with an addition problem? • 30 + ___ = 56. ___ + 30 = 56. • We can use the arrow way, counting first by either tens or ones. Try it with a partner.
Story Problem Susan has 57 cents in her piggy bank. If she just put in 30 cents today, how much did she have yesterday? • Think of the part to whole relationship! • RDW! • SHARE!
