Lesson 9: I can add decimals using place value strategies and relate those strategies to a written method. 5th Grade Module 1 – Lesson 9

Time to sprint! Your teacher will give you the sprint. 5th Grade Module 1 – Lesson 9

Get Your White Boards Ready! Say this number aloud: Record how many tenths are in th Grade Module 1 – Lesson 9 Write the number in the blank that separates the tenths… = 63 tenths _______ thousandths Write the number in the blank that separates the hundredths… = 635 hundredths _________thousandths 58 8

5th Grade Module 1 – Lesson 9 Try another problem (record on your white board): Write the number in the blank that separates the tenths… = ______ tenths _______ thousandths Write the number in the blank that separates the hundredths… = ______ hundredths _________thousandths

Let’s review Rounding Record on your white board… Say to your partner Round the number to the nearest tenth Round to the nearest hundredth 5th Grade Module 1 – Lesson 9 Say to your partner Round the number to the nearest hundredth Round to the nearest whole number

Tell your partner the decimal that is __ more than the given value. 5th Grade Module 1 – Lesson 9 ValueSAY… 5 tenths One tenth more = ___________ 5 hundredthsOne hundredth more= __________ 5 thousandthsOne thousandth more = _________ 8 hundredthsOne hundredth more = _________ 3 tenthsOne tenth more = __________ 2 thousandthsOne thousandth more = ________ Solutions 6 tenths 6 hundredths 6 thousandths 9 hundredths 4 tenths 3 thousandths *Click mouse to reveal solutions

Write the increased value on your white board. 5th Grade Module 1 – Lesson 9 ValueWrite… One thousandth more = ________ 0.35One tenth more= __________ 0.35One thousandth more = _________ 0.438One hundredth more = _________ Solutions *Click mouse to reveal solutions

5th Grade Module 1 – Lesson 9 Application Problem Ten baseballs weigh 1,417.4 grams. About how much does one baseball weigh? Round your answer to the nearest tenth of a gram. Round your answer to the nearest gram. If someone asked you, “About how much does a baseball weigh?” which answer would you give? Why? One baseball = grams grams 142 grams You would tell someone 142 grams. Let’s discuss why!

Get your place value disks and place value charts ready!! 5th Grade Module 1 – Lesson 9 Concept Development 1 Ones 0.1 Tenths 0.01 Hundredths Thousandths Problem #1: 2 tenths + 6 tenths 1.Solve 2 tenths plus 6 tenths using disks on your place value chart. 2.Say the equation in words to your partner 3.How is this addition problem the same as a whole number addition problem? How did you find the sum? Turn and share with your partner. 4.Now watch me as I model how I solved this problem

Try some more problems! Work with your partner. Use your place value mat and disks. Record your work on your whiteboard. Problem #2: 2 ones 3 thousandths + 6 ones 1 thousandth make the numbers on your place value chart 5th Grade Module 1 – Lesson 9

1 Ones 0.1 Tenths 0.01 Hundredths Thousandths ones 3 thousandths + 6 ones 1 thousandth

Let’s try another problem! Work with your partner. Use your place value mat and disks. Record your work on your whiteboard. Problem #3: 2 tenths 5 thousandths + 6 hundredths make the numbers on your place value chart 5th Grade Module 1 – Lesson 9

1 Ones 0.1 Tenths 0.01 Hundredths Thousandths 2 tenths 5 thousandths + 6 hundredths

Let’s record our last problem vertically. 1 st – write and the plus sign underneath it on your board. 2 nd – What do I need to think about when I write my second addend? Tell your partner. *click to reveal 5th Grade Module 1 – Lesson 9 1 Ones 0.1 Tenths 0.01 Hundredths Thousandths 2 tenths 5 thousandths + 6 hundredths I hope you noticed that like units should be aligned with like units. Your answer should mirror the placement of the disks on the chart

Problem #4: Use your place value chart and disks to show the addends of this problem tenths Let’s share & record the different ways we represented these addends. 5th Grade Module 1 – Lesson 9 Let’s do another one together! Which way of composing these addends requires the least amount of drawing? Why? Will the choice of units in your drawing affect your answer (sum)? Using ones and tenths because drawing 1 one disk is faster than drawing 10 tenths No! Either drawing is OK. It will still give the same answer.

5th Grade Module 1 – Lesson 9 Add. Share your thinking with your partner tenths = 18 tenths + 13 tenths 31 tenths

Let’s visualize our class discussion. Also, remember to record the vertical representation (standard algorithm) next to the chart. 5th Grade Module 1 – Lesson 9 1 Ones 0.1 Tenths 0.01 Hundredths Thousandths tenths = ______ Standard Algorithm:

Work with your partner and solve the next two problems on your place value chart and record your thinking vertically. 5th Grade Module 1 – Lesson 9 Problem #5: 1 hundred 8 hundredths + 2 ones 4 hundredths Problem #6: 148 thousandths + 7 ones 13 thousandths Think…which is the more efficient way to draw (compose) 148 thousandths.

Solve these problems on your whiteboard. For each problem… 1. Create a place value chart and record your written work. 2. Also, write the standard algorithm. Problem #7: Problem #8: Problem #9: Problem #7: Problem #8: Problem #9: th Grade Module 1 – Lesson 9

Get Ready to Complete the Problem Set on Your Own! You may use your place value chart if you need to. You will have 10 minutes to work. Try your Best! **Early Finishers – Try to generate addition problems which have 2 decimal place values, but add up to specific sums, like 1 or 2 (e.g., ). 5th Grade Module 1 – Lesson 9

Exit Ticket Time! Exit Ticket Time! 5th Grade Module 1 – Lesson 9