STEM MODEL AND EVIDENCE WORKBENCH
Build signed number-line moves and group statements for integer addition, subtraction, multiplication, and division.
Review output
Load the worked example to inspect realistic inputs, or enter anonymous classroom or laboratory evidence. Results remain in this browser tab until you copy or download them.
Transparent method
Addition combines signed quantities. Subtraction a minus b is a plus the opposite of b. Multiplication applies magnitude product and sign parity. Division asks for the factor q satisfying divisor times q equals dividend, with divisor nonzero. The engine reports the exact JavaScript numeric quotient and marks whether it is an integer. An integer result can be modeled with whole signed moves or groups. A noninteger quotient indicates that whole-number sharing is insufficient and a fraction or measurement representation is needed. Ask learners to state what zero, positive direction, negative direction, groups, and the unit mean in the problem.
Confirm the task, approved source, units, notation, signs, model assumptions, and review threshold. Keep an unchanged copy of measurements or learner responses.
Run the worked example, inspect every intermediate row, and compare the result with a hand calculation, diagram, physical model, periodic table, or approved laboratory method.
Record the method, assumptions, uncertainty, units, classifications, and flagged rows. Verify the editable report independently before instruction, assessment, or laboratory use.
How to interpret the result
Use when learners need a reasoning statement behind sign rules. Addition and subtraction use directed moves, multiplication uses equal-group and opposite patterns, and division reverses multiplication. It does not create a graphical number line to scale, infer context, diagnose reasoning, or replace counters and diagrams.
Starting at negative four and adding seven moves right to three. Subtracting negative five becomes adding positive five. Negative three multiplied by four represents four equal negative groups. Negative twenty divided by five gives negative four. Seven divided by two is retained as 3.5 and flagged for a rational extension.
Addition combines signed quantities. Subtraction a minus b is a plus the opposite of b. Multiplication applies magnitude product and sign parity. Division asks for the factor q satisfying divisor times q equals dividend, with divisor nonzero. The engine reports the exact JavaScript numeric quotient and marks whether it is an integer.
An integer result can be modeled with whole signed moves or groups. A noninteger quotient indicates that whole-number sharing is insufficient and a fraction or measurement representation is needed. Ask learners to state what zero, positive direction, negative direction, groups, and the unit mean in the problem.
Do not say two negatives always make a positive without naming the operation, turn every subtraction into movement left, divide by zero, or round a non-exact quotient into an integer. Keep parentheses and signs visible and connect symbolic rules with opposites, distance, direction, debt, temperature, or elevation.
Learning boundary
This browser-local workbench applies only the disclosed rules. It cannot diagnose learning, certify an experiment, identify a substance, establish a structure, or replace teacher, laboratory, and safety judgment.
Review checklist
Practical questions
No. Processing occurs in the current browser tab. Avoid personal information and retain authoritative records only in the school-approved system.
No. It describes entered evidence under one disclosed rule. Compare several evidence sources and ask for reasoning before drawing a conclusion.
Treat it as an editable calculation aid. Show your own reasoning, cite required sources, and follow the course method and academic-integrity rules.
YOUR NIRMION
