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What do you mean the math is MORE RIGOROUS? What’s changed?. Judith T. Brendel January 2011. Remember? “Just use the FORMULA!”. What is the average of these numbers? 80 85 90 85 70 Add them: 80 + 85 + 90 + 85 + 70 = 460 Then divide: 460/ 5 = 92 is the average.
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What do you mean the math isMORE RIGOROUS?What’s changed? Judith T. Brendel January 2011
Remember?“Just use the FORMULA!” What is the average of these numbers? 80 85 90 85 70 Add them: 80 + 85 + 90 + 85 + 70 = 460 Then divide: 460/5 = 92 is the average What is the lowest grade Carl should get on his next project to keep the same average? His grades so far are 80 90 92 88 and 80 80+90+92+88+80 = 540 540 divided by 5 = 84 He needs to get at least an 84 on his next project.
This was much faster and easier! Problem Solve not Memorize What is the average of these four test scores? 80 85 90 85 Add them up and divide by 4. 340/4 = 85 The average of these four test scores is 85. or just notice that you can borrow 5 from the 90, give it to the 80, and they’ll each be 85. 80 + 5 85 90 - 5 85 85 85 85 85 .
I needed a Why work in pairs? What should Alycia get on her next art project to raise her average by one point? On her first 5 projects she averaged 85%. Numbers were easy; I didn’t need a calculator. Now: 85 85 85 85 85 Now: 85 x 5 = 425 Needs:86 x 6 = 516 86 86 86 86 86 86 add 1 to each = + 6 more 85 + 6 = 91% on next project 515 – 425 = 91 She needs to get at least 91%.
Yes, he needs 15extra points. He could get 90 + 7 = 97 and 90 + 8 = 98 Yes, he needs 15extra points. He could get 90 + 7 = 97 and 90 + 8 = 98 Understand the Concept The highest you can get on any test is 100%. Is it still possible for Jim to get a 90% average if he has two more tests to take? His tests and project grades so far are: 8884 93 and 80 +2 +6 (3) +10 = + 15 He needs What is the lowest he can get on one of the tests and still have a 90% average? Explain! He can get a 95% on one and 100% on the other.
X2 + 13x + 36 = 0 (x ) (x ) = 0 x + 4 = 0 x + 9 = 0 x = - 4 x = -9 Check: x2 + 13x + 36 = 0 (-4)2 + 13(-4) + 36 ? 0 16– 52 + 36 = 0 -36 + 36 = 0 (-9)2 + 13(-9) + 36 ? 0 81- 117 + 36 = 0 -36 + 36 = 0 2) X2 - 16x - 36 = 0 (x ) (x ) = 0 Why is it so important to be neat and organized? Why memorize facts? + 2 -18 + 4 + 9 3) X2 + 9x - 36 = 0 (x ) (x ) = 0 - 3 +12 4) X2 -37x + 36 = 0 (x ) (x ) = 0 - 1 - 36
6 3 14 SEE the CHANGES? 6 x 3 = 18 (8x3)/2=12 Total = 30 sq. 3 6 48/4 = 12 12 x 12 = 144
Shaded area = 12 - s 3 12 Area of the square = 144 sq.units