Python in plain terms

In blocks, you placed text in a say block and ran it. Here print names Python's display function. The opening parenthesis begins its arguments, and the closing parenthesis ends them. The quotes mark the text to display; Python does not print those outer quotes. The editor is where instructions belong. Output is where their result appears. Typing or editing a line alone does not execute it: pressing Run does. A function is a named procedure; for now you are calling an existing one.

Type the line yourself, or load it, and predict the exact message before running. Watch the loading status if this is the first Python run.

name = "Ada" is the typed equivalent of setting a variable named name to the text Ada. Read = as 'store the value on the right under the name on the left'. On the next line, name has no quotes because Python should look up that stored value. In print("Hello", name), the comma separates two arguments; print puts a space between their displayed forms. Running starts at the first line again, so the assignment occurs before the lookup.

Run once, then change only the value assigned to name and run again. Both lines together are a complete program.

age = 14 stores an integer: a whole number. The greeting is a string: text. Quotes distinguish the string "14" from the number 14 even though their printed forms look alike. Names are case-sensitive, so age and Age are different names. A good name describes a value, such as image_count or accuracy. It may contain letters, digits, and underscores, but cannot start with a digit or contain spaces. Avoid replacing useful built-in names such as print or list.

Find the two assignments and the two display calls. Run and compare the displayed number with its code.

The right-hand side of next_age = age + 1 is evaluated first. With age equal to 14, the addition produces 15; next_age then refers to that result. This is the same as putting an addition block into a variable's value slot. The original age is still 14 because this line assigns to a different name. age = age + 1 would instead replace age's value. Arithmetic uses +, -, *, /, and ** for powers. Parentheses can group calculations, just as nested number blocks group operations.

Before Run, calculate next_age for your chosen age. Then change the added amount from 1 to 2 and rerun.

if next_age >= 15: asks a question. The >= comparison returns a boolean, True or False. The colon introduces the branch, and the four spaces before its print line say that instruction belongs inside the branch. else: is aligned with if, and its indented line handles the false case. In blocks, the C-shaped if block enclosed its contents. In Python, indentation shows that same enclosure. This threshold is a made-up example, not an age rule for using this website.

Run once with age 14 and once with age 10. Keep four spaces before each branch's print instruction.

A single equals sign assigns a value. Two equals signs, ==, ask whether two values are equal. != asks whether they differ. Comparisons return True or False, without quotation marks: those are boolean values, not words. and requires both questions to be true; or requires at least one; not reverses a boolean. These are the typed versions of the question-shaped logic blocks you used earlier. A successful comparison does not store a new age.

Predict each of the three booleans for your age before running. Change age and test the predictions.

A program can receive values instead of fixing them in its source. input("Name: ") pauses the running program and displays a clear prompt in Terminal; type a fictional name, then press Enter or Send. It returns that text. int(input("Age: ")) pauses at the next prompt, then converts the entered numeric text to an integer. The nested calls play the same role as a number-conversion block around an answer block. Answer with Ada and 14, not assignments or quote marks.

Load the stage and press Run. Answer the Name: prompt, then answer the Age: prompt in Terminal. Run again with two different fictional answers.

Adding two numbers performs arithmetic. Adding two strings joins them. Thus 8 + 1 is 9, while "8" + "1" is the text 81. int converts valid whole-number text; it does not infer the meaning of every word. Division with / produces a decimal-valued float, so 17 / 20 is 0.85. type tells you the kind of value you supplied. This inspection is useful when a program reads a CSV or user input and receives strings where a numerical model needs numbers.

Predict the first four outputs, then run. Read the four type names as evidence about values, not something to memorise for a quiz.

These counts are a fictional evaluation for learning Python. Accuracy is the number correct divided by the number evaluated. round(accuracy, 3) returns a value rounded for display; it does not change accuracy because we did not assign the result back. Multiplying a proportion by 100 expresses a percentage. A target of 0.8 is a teaching choice, not a universal definition of a useful model. An error such as misspelling correct is different from a logic mistake such as dividing by the wrong total: both deserve checking.

Run, then trace the path from correct and total to the displayed percentage. Keep total positive and correct between zero and total.

You have now typed the same categories of instructions as blocks: display, named values, arithmetic, terminal input, and decisions. The comment begins with # and explains a choice without becoming an instruction. Blank lines group related work. If an error occurs, read the final error message and the indicated source line. NameError often means a misspelled or not-yet-created name; SyntaxError may point to a missing quote, bracket, or colon; an indentation error points to the structure that blocks previously drew for you. Repair one cause, then run the whole program again.

Build your own final version in the lesson editor. Run it twice: answer the prompts once for each branch, then compare with the folded reference only after trying.