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Notes – Percents of Change (Day 4). Thursday, October 23, 2014 We are learning to… solve for parts, totals, and percents using proportional reasoning. Percents of Change. Today we will be looking for percents of change . We will be given two totals: A total before the change.
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Notes – Percents of Change (Day 4) Thursday, October 23, 2014 We are learning to… solve for parts, totals, and percents using proportional reasoning.
Percents of Change • Today we will be looking for percents of change. • We will be given two totals: • A total before the change. • And a total after the change. • Our job is to: • Find the change (or difference) between the two totals. • This change represents the missing part. • Then compare this part to the original total. • Solve for the missing percent which represents the change between the totals.
Finding a Percent of Change The original total was:______ and then the amount changed to:_______. In the first grading period 40 people received A’s in Mrs. Hauptman’s class. In the second grading period 70 people received A’s. What is the percent of increase from the first quarter to the second quarter? 40 70 The amount of change: (Increase or Decrease) This change represents the PART! 70 – 40 = 30 Find the percent of change from the original total: Solution as a sentence: Table: (Remember to use the original total) “75% more students had A’s for the second quarter than the first quarter.” Parts Totals 30 40 (100) (100) 100 x
Finding a Percent of Change The original total was:______ and then the amount changed to:_______. On Monday 215 students bought lunch and on Tuesday only 172 student bought lunch. What is the percent of decrease of students who bought lunch from Monday to Tuesday? 215 172 The amount of change: (Increase or Decrease) 215 – 172 = 43 This change represents the PART! Find the percent of change from the original total: Solution as a sentence: Table: (Remember to use the original total) “20% less students bought lunch on Tuesday compared to Monday.” Parts Totals (100) (100) 43 215 100 x
Independent Practice • Find the following percents of increase and decrease quietly and independently. • State your solution in form for a complete sentence relating back to the problem. • When you are finished quietly raise your hand to have your teacher check your solutions.
Group Practice • The group who works best together today will have their homework assignment cut in half…we’re looking for a group who can: • Stay in the same place…no one rushes ahead or falls behind • Help each other with the assignment • Stay focused on math • Be sure to analyze each question carefully before attempting to find the solution. • Underline or circle important words to help.