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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 177 · 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.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) blinks an LED (d) joins two wires
  2. 2.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) prints 1 (c) takes 1 away (d) adds 1 to count
  3. 3.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  4. 4.🔁 x = 2
    repeat 5 times { x = x × 2 }
    What is x at the end?
  5. 5.🔁 repeat 5 times { repeat 3 times { beep } }
    How many beeps are there?
  6. 6.🔁 repeat 6 times { repeat 6 times { beep } }
    How many beeps are there?
  7. 7.🔁 count = 1
    while (count < 9) { count = count + 4 }
    How many times does the loop run?
  8. 8.🔁 count = 1
    repeat 7 times { count = count + 3 }
    What is count at the end?
  9. 9.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
  10. 10.🔁 count = 5
    repeat 4 times { count = count + 2 }
    What is count at the end?
  11. 11.🔁 count = 2
    while (count < 20) { count = count + 3 }
    How many times does the loop run?
  12. 12.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
  13. 13.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
  14. 14.🔁 count = 0
    while (count < 6) { count = count + 2 }
    How many times does the loop run?
  15. 15.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
  16. 16.🔁 x = 2
    repeat 1 time { x = x × 2 }
    What is x at the end?
  17. 17.🔁 count = 2
    repeat 6 times { count = count + 8 }
    What is count at the end?
  18. 18.🔁 count = 10
    repeat 4 times { count = count + 6 }
    What is count at the end?
  19. 19.🔁 x = 5
    repeat 2 times { x = x × 2 }
    What is x at the end?
  20. 20.🔁 count = 3
    while (count < 11) { count = count + 4 }
    How many times does the loop run?
  21. 21.🔁 count = 2
    while (count < 22) { count = count + 5 }
    How many times does the loop run?
  22. 22.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
  23. 23.🔁 count = 7
    repeat 10 times { count = count + 8 }
    What is count at the end?
  24. 24.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
  25. 25.🔁 count = 1
    repeat 3 times { count = count + 8 }
    What is count at the end?
  26. 26.🔁 count = 1
    repeat 10 times { count = count + 9 }
    What is count at the end?
  27. 27.🔁 count = 2
    while (count < 8) { count = count + 2 }
    How many times does the loop run?
  28. 28.🔁 count = 4
    while (count < 14) { count = count + 5 }
    How many times does the loop run?
  29. 29.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
  30. 30.🔁 count = 0
    while (count < 40) { count = count + 5 }
    How many times does the loop run?
  31. 31.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  32. 32.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
  33. 33.🔁 repeat 3 times { repeat 4 times { beep } }
    How many beeps are there?
  34. 34.🔁 repeat 2 times { repeat 4 times { beep } }
    How many beeps are there?
  35. 35.🔁 count = 5
    while (count < 17) { count = count + 3 }
    How many times does the loop run?
  36. 36.🔁 count = 4
    while (count < 36) { count = count + 4 }
    How many times does the loop run?
  37. 37.🔁 repeat 5 times { repeat 2 times { beep } }
    How many beeps are there?
  38. 38.🔁 total = 0
    for i = 1 to 9 { total = total + i }
    What is total at the end?
  39. 39.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
  40. 40.🔁 count = 4
    while (count < 14) { count = count + 2 }
    How many times does the loop run?

Answer key

  1. stores a value
  2. adds 1 to count
  3. 78
  4. 64
  5. 15
  6. 36
  7. 2
  8. 22
  9. 66
  10. 13
  11. 6
  12. 21
  13. 15
  14. 3
  15. 55
  16. 4
  17. 50
  18. 34
  19. 20
  20. 2
  21. 4
  22. 160
  23. 87
  24. 24
  25. 25
  26. 91
  27. 3
  28. 2
  29. 32
  30. 8
  31. 10
  32. 15
  33. 12
  34. 8
  35. 4
  36. 8
  37. 10
  38. 45
  39. 12
  40. 5

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