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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 457 · 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 = 1
    repeat 10 times { count = count + 3 }
    What is count at the end?
  2. 2.🔁 count = 2
    while (count < 10) { count = count + 4 }
    How many times does the loop run?
  3. 3.🔁 repeat 6 times { repeat 5 times { beep } }
    How many beeps are there?
  4. 4.🔁 What does a variable do in a program? (a) blinks an LED (b) stores a value (c) measures light (d) joins two wires
  5. 5.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
  6. 6.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
  7. 7.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
  8. 8.🔁 count = 7
    repeat 7 times { count = count + 10 }
    What is count at the end?
  9. 9.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) prints 1 (c) takes 1 away (d) adds 1 to count
  10. 10.🔁 count = 2
    while (count < 17) { count = count + 5 }
    How many times does the loop run?
  11. 11.🔁 count = 1
    while (count < 21) { count = count + 5 }
    How many times does the loop run?
  12. 12.🔁 repeat 4 times { repeat 4 times { beep } }
    How many beeps are there?
  13. 13.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
  14. 14.🔁 count = 3
    repeat 3 times { count = count + 4 }
    What is count at the end?
  15. 15.🔁 count = 4
    while (count < 20) { count = count + 2 }
    How many times does the loop run?
  16. 16.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  17. 17.🔁 count = 1
    repeat 8 times { count = count + 7 }
    What is count at the end?
  18. 18.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
  19. 19.🔁 x = 1
    repeat 4 times { x = x × 2 }
    What is x at the end?
  20. 20.🔁 count = 0
    while (count < 12) { count = count + 2 }
    How many times does the loop run?
  21. 21.🔁 count = 5
    repeat 9 times { count = count + 2 }
    What is count at the end?
  22. 22.🔁 count = 0
    repeat 8 times { count = count + 2 }
    What is count at the end?
  23. 23.🔁 count = 4
    while (count < 18) { count = count + 2 }
    How many times does the loop run?
  24. 24.🔁 count = 3
    while (count < 11) { count = count + 2 }
    How many times does the loop run?
  25. 25.🔁 count = 4
    while (count < 39) { count = count + 5 }
    How many times does the loop run?
  26. 26.🔁 count = 1
    while (count < 26) { count = count + 5 }
    How many times does the loop run?
  27. 27.🔁 x = 3
    repeat 4 times { x = x × 2 }
    What is x at the end?
  28. 28.🔁 count = 0
    repeat 5 times { count = count + 2 }
    What is count at the end?
  29. 29.🔁 repeat 3 times { repeat 2 times { beep } }
    How many beeps are there?
  30. 30.🔁 count = 6
    repeat 7 times { count = count + 9 }
    What is count at the end?
  31. 31.🔁 count = 2
    while (count < 22) { count = count + 4 }
    How many times does the loop run?
  32. 32.🔁 count = 2
    while (count < 30) { count = count + 4 }
    How many times does the loop run?
  33. 33.🔁 count = 2
    repeat 10 times { count = count + 5 }
    What is count at the end?
  34. 34.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
  35. 35.🔁 repeat 3 times { repeat 3 times { beep } }
    How many beeps are there?
  36. 36.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
  37. 37.🔁 count = 0
    repeat 3 times { count = count + 4 }
    What is count at the end?
  38. 38.🔁 repeat 2 times { repeat 2 times { beep } }
    How many beeps are there?
  39. 39.🔁 count = 2
    repeat 3 times { count = count + 10 }
    What is count at the end?
  40. 40.🔁 count = 0
    while (count < 15) { count = count + 3 }
    How many times does the loop run?

Answer key

  1. 31
  2. 2
  3. 30
  4. stores a value
  5. 10
  6. 55
  7. 15
  8. 77
  9. adds 1 to count
  10. 3
  11. 4
  12. 16
  13. 12
  14. 15
  15. 8
  16. 10
  17. 57
  18. 21
  19. 16
  20. 6
  21. 23
  22. 16
  23. 7
  24. 4
  25. 7
  26. 5
  27. 48
  28. 10
  29. 6
  30. 69
  31. 5
  32. 7
  33. 52
  34. 32
  35. 9
  36. 15
  37. 12
  38. 4
  39. 32
  40. 5

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