Trace the strings: indexing and slicing: coding worksheet for Grades 10–12, page 1 preview

Coding worksheet · Coding

Trace the strings: indexing and slicing · Grades 10–12

Read 6 short Python programs about string indexing, slicing and loops over letters and work out by hand what each one prints or the final value of a variable. Builds careful code tracing.

Grades 10–12 · ages 15 to 18
Easy
25 to 35 minutes
1 page
Free

The answer key is a separate page for grown-ups. Sign in to download it.

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The programs to trace

Directions: Trace each program line by line without a computer. Keep a note of every variable as it changes, then write exactly what the program prints or the final value.

1 What is printed?
1 word = "puzzle"
2 print(word[0] + word[-1])
2 What is printed?
1 word = "garden"
2 count = 0
3 for ch in word:
4 if ch == "a" or ch == "e":
5 count += 1
6 print(count)
3 What is printed?
1 def frame(word, edge):
2 return edge + word + edge
3 print(len(frame("banana", "**")))
4 What is printed?
1 text = "violin"
2 result = ""
3 for ch in text:
4 result = ch + result
5 print(result)
5 What is printed? Write each line.
1 for i in range(3, 0, -1):
2 print("*" * i)
6 What is printed?
1 word = "banana"
2 print(len(word), word[3])

What your child practices

Your child builds careful code tracing.

Grades and ages: Grades 10–12, ages 15 to 18
Time: About 25 to 35 minutes
Subject: Coding
Level: Easy for Grades 10–12
Answer key: Yes, for grown-ups who sign in
Printing: 1 page, US Letter or A4, low-ink option
Updated: October 15, 2026

How to use it

Work through the first program together, one line or arrow at a time. Then let your child work through the rest, showing their thinking on the page. It is one of the easier sheets for Grades 10–12, good as a warm-up or a first look at the topic.

An answer key comes with it as a separate page that grown-ups download after signing in.

Tip for grown-ups: Have your child write each variable's value beside its line as they trace.

Done on paper? A grown-up can record it on the child's page in PlayOwl; downloading alone doesn't count as finished.