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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 430 · 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 = 2
    while (count < 8) { count = count + 3 }
    How many times does the loop run?
  2. 2.🔁 What does a variable do in a program? (a) joins two wires (b) blinks an LED (c) stores a value (d) measures light
  3. 3.🔁 repeat 6 times { repeat 6 times { beep } }
    How many beeps are there?
  4. 4.🔁 repeat 6 times { repeat 3 times { beep } }
    How many beeps are there?
  5. 5.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
  6. 6.🔁 x = 3
    repeat 5 times { x = x × 2 }
    What is x at the end?
  7. 7.🔁 repeat 3 times { repeat 6 times { beep } }
    How many beeps are there?
  8. 8.🔁 total = 0
    for i = 1 to 8 { total = total + i }
    What is total at the end?
  9. 9.🔁 total = 0
    for i = 1 to 9 { total = total + i }
    What is total at the end?
  10. 10.🔁 count = 2
    repeat 7 times { count = count + 7 }
    What is count at the end?
  11. 11.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
  12. 12.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  13. 13.🔁 x = 4
    repeat 2 times { x = x × 2 }
    What is x at the end?
  14. 14.🔁 count = 1
    repeat 9 times { count = count + 4 }
    What is count at the end?
  15. 15.🔁 repeat 6 times { repeat 2 times { beep } }
    How many beeps are there?
  16. 16.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
  17. 17.🔁 count = 6
    repeat 6 times { count = count + 2 }
    What is count at the end?
  18. 18.🔁 count = 3
    while (count < 17) { count = count + 2 }
    How many times does the loop run?
  19. 19.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  20. 20.🔁 repeat 4 times { repeat 5 times { beep } }
    How many beeps are there?
  21. 21.🔁 repeat 2 times { repeat 2 times { beep } }
    How many beeps are there?
  22. 22.🔁 repeat 2 times { repeat 5 times { beep } }
    How many beeps are there?
  23. 23.🔁 x = 5
    repeat 3 times { x = x × 2 }
    What is x at the end?
  24. 24.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
  25. 25.🔁 count = 0
    repeat 7 times { count = count + 9 }
    What is count at the end?
  26. 26.🔁 count = 0
    repeat 8 times { count = count + 5 }
    What is count at the end?
  27. 27.🔁 count = 1
    repeat 10 times { count = count + 8 }
    What is count at the end?
  28. 28.🔁 What does “count = count + 1” do? (a) takes 1 away (b) prints 1 (c) sets count to 1 (d) adds 1 to count
  29. 29.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
  30. 30.🔁 count = 0
    repeat 6 times { count = count + 9 }
    What is count at the end?
  31. 31.🔁 count = 1
    while (count < 5) { count = count + 2 }
    How many times does the loop run?
  32. 32.🔁 x = 2
    repeat 5 times { x = x × 2 }
    What is x at the end?
  33. 33.🔁 repeat 4 times { repeat 4 times { beep } }
    How many beeps are there?
  34. 34.🔁 count = 3
    repeat 7 times { count = count + 5 }
    What is count at the end?
  35. 35.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
  36. 36.🔁 repeat 5 times { repeat 6 times { beep } }
    How many beeps are there?
  37. 37.🔁 count = 4
    while (count < 32) { count = count + 4 }
    How many times does the loop run?
  38. 38.🔁 x = 3
    repeat 1 time { x = x × 2 }
    What is x at the end?
  39. 39.🔁 count = 0
    while (count < 24) { count = count + 4 }
    How many times does the loop run?
  40. 40.🔁 count = 0
    repeat 6 times { count = count + 4 }
    What is count at the end?

Answer key

  1. 2
  2. stores a value
  3. 36
  4. 18
  5. 160
  6. 96
  7. 18
  8. 36
  9. 45
  10. 51
  11. 2
  12. 78
  13. 16
  14. 37
  15. 12
  16. 24
  17. 18
  18. 7
  19. 10
  20. 20
  21. 4
  22. 10
  23. 40
  24. 21
  25. 63
  26. 40
  27. 81
  28. adds 1 to count
  29. 32
  30. 54
  31. 2
  32. 64
  33. 16
  34. 38
  35. 15
  36. 30
  37. 7
  38. 6
  39. 6
  40. 24

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