DMS · School Lab · Teacher card
Balance Scale
The big question: Does the equals sign mean “write the answer”, or “both sides are the same”?
Goal: Children read the equals sign as “both sides are the same”, not “write the answer”, and find the number for the box by comparing both sides.
In the lesson
Lesson flow
| Step | What children do | min |
|---|---|---|
| 1 · Ready? | Meets the empty balance and the drawer of cubes, and sees a pan go down when a cube goes in. | ≤ 1 |
| 2 · What do I know? | Shows with fingers what goes in the box in 8 + 4 = □ + 5; nobody is told right or wrong (grade 1: which is heavier, the foam cube or the iron cube?). | 1 |
| 3 · In everyday life | Thinks about two friends balancing on a seesaw and the scales at the greengrocer's. | 1 |
| 4 · Predict | Chooses how many cubes to put in the box: 12, 17 or 7? The prediction is locked in. | 1–2 |
| 5 · Try and observe | The cubes drop into the box; with 12, the box's pan sinks. Replays the moment. | 2–5 |
| 6 · Why? | Sees that the equals sign says both sides are the same; the balance line lights up as “=”. | 2–4 |
| 7 · Try something new | Predicts first, then tries new equations; in grade 4, levels an unbalanced scale by adding or taking away cubes. | 2–6 |
| 8 · My explorer notebook | Picks the balanced scale out of three pictures and sees the prediction next to the result. | 1–3 |
| Off-screen activity, discussion and wrap-up | ≈ 15 | |
Class prediction vote
8 + 4 = □ + 5. How many cubes go in the box?
Discussion questions
- Why 7? How do you know?
- What if we put 12 in the box? Which way would the scale tip?
- What is the equals sign telling us?
Avoid saying: “After the equals sign, we write the answer.”
Say instead: “The equals sign shows that both sides are the same.”
Off-screen activity for the teacher's desk: Hanger balance
Tie a paper cup to each end of a clothes hanger; one pupil holds the hanger up by a pencil. Put the same empty box in each cup and secretly hide some units in one. The class predicts first, then you open the box.
You need: A clothes hanger · Two paper cups and string · Identical units: paper clips, cubes or marbles · Two empty boxes of the same size
Details
Grades and learning outcomes
- Grade 1: MAT.1.1.8 (Maarif Model 2026), MAT.1.2.3 (Maarif Model 2026)
- Grade 2: MAT.2.2.6 (Maarif Model 2026)
- Grade 3: MAT.3.2.8 (Maarif Model 2026)
- Grade 4: M.4.1.5.7 (2018 curriculum), M.4.1.5.8 (2018 curriculum) · Equivalent from 2027–28: MAT.4.2.9
Scope
There is one mystery box per task. The rule “add or take away the same on both sides” (a grade 7 topic) is not taught; ≠ appears only in grade 4.
Misconceptions
- “Equals means write the answer.” (12 or 17 for 8 + 4 = □ + 5) → With 12 in the box, its pan sinks; with 7, the scale levels out.
- “Bigger things are heavier.” (grade 1) → The pan with the small iron cube goes down; the big foam cube stays up.
Getting ready
- Open the lab on the board or a tablet and pick the grade.
- For the screen-free activity: a clothes hanger, two paper cups, string and identical units (same-size paper clips, cubes or marbles).
- In grade 1, don't use the + and = signs before the “What does equals mean?” scene (spring term).
This lab is mapped to learning outcomes M.4.1.5.7 and M.4.1.5.8 of the Turkish Ministry of National Education's 2018 Mathematics curriculum. It has not been reviewed or approved by the Ministry of National Education (MEB) or its Board of Education (TTKB).
This lab is mapped to learning outcomes MAT.1.1.8, MAT.1.2.3, MAT.2.2.6 and MAT.3.2.8 of the Turkish Ministry of National Education's Türkiye Century Maarif Model Mathematics curriculum (2026 version). It has not been reviewed or approved by the Ministry of National Education (MEB) or its Board of Education (TTKB).
From the 2027–28 school year, the grade 4 equivalent in the Türkiye Century Maarif Model is MAT.4.2.9.