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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 310 · 40 questions
TalentJR

Remember (Trace every pass): count = count + k adds k each time round; after n rounds: start + n × k. A loop inside a loop runs outer × inner times. while (condition) repeats until the condition is false — count the rounds as you trace.

NameDateTime takenScore ___ / 40
  1. 1.🔁 count = 7
    repeat 9 times { count = count + 10 }
    What is count at the end?
  2. 2.🔁 repeat 3 times { repeat 3 times { beep } }
    How many beeps are there?
  3. 3.🔁 count = 2
    repeat 7 times { count = count + 2 }
    What is count at the end?
  4. 4.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) takes 1 away (c) adds 1 to count (d) prints 1
  5. 5.🔁 count = 6
    repeat 7 times { count = count + 6 }
    What is count at the end?
  6. 6.🔁 x = 5
    repeat 4 times { x = x × 2 }
    What is x at the end?
  7. 7.🔁 count = 2
    repeat 5 times { count = count + 9 }
    What is count at the end?
  8. 8.🔁 count = 10
    repeat 4 times { count = count + 2 }
    What is count at the end?
  9. 9.🔁 What does a variable do in a program? (a) blinks an LED (b) measures light (c) stores a value (d) joins two wires
  10. 10.🔁 count = 1
    while (count < 13) { count = count + 3 }
    How many times does the loop run?
  11. 11.🔁 count = 2
    while (count < 22) { count = count + 4 }
    How many times does the loop run?
  12. 12.🔁 count = 5
    repeat 5 times { count = count + 6 }
    What is count at the end?
  13. 13.🔁 x = 1
    repeat 5 times { x = x × 2 }
    What is x at the end?
  14. 14.🔁 count = 2
    while (count < 8) { count = count + 2 }
    How many times does the loop run?
  15. 15.🔁 count = 0
    while (count < 14) { count = count + 2 }
    How many times does the loop run?
  16. 16.🔁 count = 2
    repeat 4 times { count = count + 5 }
    What is count at the end?
  17. 17.🔁 repeat 3 times { repeat 2 times { beep } }
    How many beeps are there?
  18. 18.🔁 count = 0
    while (count < 10) { count = count + 2 }
    How many times does the loop run?
  19. 19.🔁 count = 4
    while (count < 19) { count = count + 5 }
    How many times does the loop run?
  20. 20.🔁 count = 8
    repeat 5 times { count = count + 4 }
    What is count at the end?
  21. 21.🔁 repeat 3 times { repeat 6 times { beep } }
    How many beeps are there?
  22. 22.🔁 count = 0
    while (count < 12) { count = count + 3 }
    How many times does the loop run?
  23. 23.🔁 x = 5
    repeat 3 times { x = x × 2 }
    What is x at the end?
  24. 24.🔁 x = 1
    repeat 4 times { x = x × 2 }
    What is x at the end?
  25. 25.🔁 count = 2
    while (count < 12) { count = count + 2 }
    How many times does the loop run?
  26. 26.🔁 x = 4
    repeat 2 times { x = x × 2 }
    What is x at the end?
  27. 27.🔁 count = 8
    repeat 8 times { count = count + 8 }
    What is count at the end?
  28. 28.🔁 total = 0
    for i = 1 to 3 { total = total + i }
    What is total at the end?
  29. 29.🔁 count = 2
    repeat 6 times { count = count + 3 }
    What is count at the end?
  30. 30.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?
  31. 31.🔁 repeat 5 times { repeat 3 times { beep } }
    How many beeps are there?
  32. 32.🔁 x = 2
    repeat 2 times { x = x × 2 }
    What is x at the end?
  33. 33.🔁 count = 5
    while (count < 13) { count = count + 4 }
    How many times does the loop run?
  34. 34.🔁 count = 10
    repeat 4 times { count = count + 6 }
    What is count at the end?
  35. 35.🔁 count = 4
    repeat 9 times { count = count + 3 }
    What is count at the end?
  36. 36.🔁 count = 0
    while (count < 16) { count = count + 4 }
    How many times does the loop run?
  37. 37.🔁 count = 1
    repeat 10 times { count = count + 3 }
    What is count at the end?
  38. 38.🔁 count = 6
    repeat 7 times { count = count + 2 }
    What is count at the end?
  39. 39.🔁 x = 3
    repeat 3 times { x = x × 2 }
    What is x at the end?
  40. 40.🔁 count = 3
    repeat 8 times { count = count + 3 }
    What is count at the end?

Answer key

  1. 97
  2. 9
  3. 16
  4. adds 1 to count
  5. 48
  6. 80
  7. 47
  8. 18
  9. stores a value
  10. 4
  11. 5
  12. 35
  13. 32
  14. 3
  15. 7
  16. 22
  17. 6
  18. 5
  19. 3
  20. 28
  21. 18
  22. 4
  23. 40
  24. 16
  25. 5
  26. 16
  27. 72
  28. 6
  29. 20
  30. 28
  31. 15
  32. 8
  33. 2
  34. 34
  35. 31
  36. 4
  37. 31
  38. 20
  39. 24
  40. 27

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