Mood Radio Variables

Overview

Students build the foundational Mood Radio program: one micro:bit sends a number, the other receives it and displays a matching mood icon. Along the way, students use rational-number ideas (signed values, additive inverses, and division as a rational quotient) to reason about what “numbers mean” in communication.

Learning intentions

Students will be able to:

• Represent a signed number choice as a numeric “mood code” to send over radio.
• Explain why subtracting a number is the same as adding its opposite.
• Interpret a received integer quotient as a rational number (no division by zero) and use that idea to select a mood threshold.
• Connect variable values to real meanings (moods and LED icons) in a micro:bit program.

Success criteria

Students can:

• Match at least three mood codes to correct emoji/LED icons on the receiver.
• Correctly use one or more variables to send and receive a number via radio.
• Use the idea that “p − q is p + (−q)” to justify a simple mood-threshold rule.
• Compute and interpret a simple signed quotient like −6/3 as a rational number and identify the sign.

Curriculum links

• The Number System — addition and subtraction of rational numbers and number line meaning (7.NS.A.1).
• The Number System — additive inverses and interpreting sums (7.NS.A.1b).
• The Number System — signed multiplication (used for sign reasoning in mood codes) (7.NS.A.2a).
• The Number System — quotient of integers as rational numbers and sign rules (7.NS.A.2b).

Lesson structure (45 minutes)

1. 0–5 min · Hook (Mood Codes). Teacher shows two sample Mood Radio screens: receiver emoji changes when transmitter “sends” a code; students predict what code might represent “happy” vs “sad.” Students answer with a quick think-pair-share: “What kind of numbers could represent emotions?”

2. 5–12 min · Mini-lesson: Variables as Meaning. Teacher introduces variables as “named storage” (e.g., moodCode) and radio messaging (send integer, receive integer), then connects to math meaning: positive vs negative codes for different emotion directions (e.g., good vs not-so-good). Students take notes: define moodCode and list two example codes (one positive, one negative).

3. 12–20 min · Guided MakeCode Build: Starter Map. Teacher walks step-by-step through the starter structure:

• Transmitter sets moodCode (integer) and sends it via radio
• Receiver receives it into receivedCode and uses it to choose an icon/emoji Students follow along assembling the guided MakeCode blocks for sending a number and mapping at least 3 codes to LED icons.

4. 20–28 min · Math Checkpoint: Additive Inverses in Code Choice. Teacher poses a code-selection rule tied to CCSS meaning: “If your baseline mood is 2 and the effect is −3, the adjusted mood code is 2 + (−3).” Then states subtraction equivalence: “2 − 3 equals 2 + (−3).” Students compute the adjusted mood code and identify the opposite they added (e.g., opposite of 3 is −3).

5. 28–36 min · Math Checkpoint: Division and Rational Quotients for Thresholds. Teacher sets up a simple threshold rule to decide mood icon: “Use a signed quotient to scale the received code into a mood category; never divide by 0.” Example: “If receivedCode is −6 and you divide by 3, the quotient is −2 (a rational number).” Students do a quick pair computation: pick one example division by a nonzero integer and predict which side of the threshold they should fall on.

6. 36–43 min · Debug Relay: Two micro:bits, One Rule. Teacher organizes students into groups of 2–3 with a transmitter and receiver; groups test three mood codes and confirm the correct icons appear. Students run a “debug relay”: one student changes moodCode, another checks receiver output, and a third explains the mapping using math language (sign, opposite, quotient).

7. 43–45 min · Exit Ticket (1 minute + turn-in). Teacher collects a short written response. Students answer: “Explain why subtracting a number is the same as adding its opposite, and give one example using your mood codes.”

Resources

• 25 micro:bit kits (or stations with at least 13 transmitters + 12 receivers)
• MakeCode environment with Mood Radio starter template available offline/on devices
• Student coding handout: “Mood Code Map” table (code → icon)
• Printed sign/rational quick reference card (opposites and “division by nonzero only”)
• Timer for station rotations
• Markers + sticky notes for quick debugging labels (e.g., “code mismatch”)

Assessment

• Formative checks during build: teacher observes whether students correctly send an integer and map received values to icons.
• Targeted questioning at checkpoints:
• Additive inverses: can students state that p − q = p + (−q)?
• Quotients: can students interpret the sign of a rational quotient from a simple division?
• Exit ticket: written explanation plus a concrete example.

Differentiation

• Support:
• Provide a partially completed MakeCode project with only the mapping blocks left blank.
• Offer sentence starters for the exit ticket: “Subtracting q is adding … because …”
• Use a mood-code mapping anchor chart with color-coded sign cues (+ green, − red).
• Extension:
• Challenge students to use a threshold based on a signed quotient (e.g., if receivedCode/3 is less than −1, show “down” icon).
• Ask them to justify the sign of the quotient and link it to the chosen mood icon.
• EAL/SEN:
• Reduce language load by allowing “math word banks” (opposite, subtract, quotient, nonzero).
• Permit verbal explanation while the student writes one sentence on the exit ticket (teacher can transcribe essentials).