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25.  Today is March 17. Write down as many equations as you can, each equaling to 17.

  • 102 – 83 = 17
  • sqrt(289) = 17
  • (15 + 4) – 2 = 17
  • 42 + 1 = 17
  • sqrt(9) + 14 = 17
  • abs(-16 – 1) = 17
  • 25 – 15 = 17
  • 52 – 8 = 17

26.  How would you find the area of the shaded?

This 4-leaf clover was created by drawing 4 semicircles of radius equal to 1/2 of side of square.
Picture
Student 1
  • Find area of square
  • Find area of circle
  • Subtract circle from square, this leaves area of the 2 white parts
  • Subtract 2 white parts from circle gives only the shaded parts
Picture
Student 2
  • Find area of square
  • Find area of 1 semicircle
  • Multiply this by 4
  • Subtract area of square from area of 4 semicircles gives you the shaded part only

Student 3
I drew in the 2 segments to hint students at this strategy.
  • Find area of 1/4 of circle
  • Find area of right triangle within the quarter circle
  • Subtract to get half the leaf part
  • Multiply this by 8
Picture

27. How much bigger is california than oregon?

Picture
Answer: California’s area is 163,695 square miles, about 1.7 times larger.
Student 1
  • Twice as big.
  • I rounded up to 100000 square miles. That times 2 to get 200000. I subtracted 1400 from 200000 because I’d rounded up, so about 198600.

Student 2
  • I think California is about 1.5 times bigger.
  • I took half of 98380 to get 49190. Then I added this to 98380 to get 147570.

Student 3
  • I think it’s 1.7 times bigger.
  • I rounded up to 100000 square miles, so around 170000 is my estimate.

28.  Today is March 21. Write down as many equations as you can, each equaling to 21.

  • 620 ÷ 2 – 300 + 11 = 21
  • 52 – 4 = 21
  • 85 – 64 = 21
  • sqrt(36) × 3 + 3 = 21
  • sqrt(400) + 1 = 21
  • 42 × 2 – 11 = 21
  • 4! – 3 = 21
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