NP10
Proportional Reasoning
Solve scaling problems involving direct and inverse relationships.
Verify if a relationship is directly proportional using the "Zero Test" and "Doubling Test", and fill in missing values on pre-drawn Double Number Lines using multiplicative jumps.
Complete ratio tables with missing values using the unitary method (finding the value of 1) through multiplication and division.
Memorize and calculate decimal multipliers for percentage increases (e.g., +12% = \times 1.12) and apply them to baseline values in a single multiplicative step.
Extract data from real-world contexts and build Double Number Lines or Ratio Tables to solve direct proportion word problems.
Differentiate inverse proportion from direct proportion using the "Halving Test" and fill intuitive gaps in sharing and working contexts.
Calculate decimal multipliers for percentage decreases and apply them to baseline values using a single multiplication step.
Use reciprocal operations (multiplying one side while dividing the other) to complete ratio tables for inverse proportion contexts.
Use the Zero, Doubling, and Halving tests to classify real-world contexts as direct proportion, inverse proportion, or neither.
Use the unitary method to find the cost per 1 item or cost per 100g to compare two options and determine Best Buy.
Apply direct proportion using Double Number Lines and Ratio Tables to scale single ingredients and full recipe grids up and down.
Students will convert currencies one-way and backwards using ratio tables with a fixed multiplier.
Determine the exact percentage increase or decrease between two values by finding the multiplier first.
Students will track units carefully through 2- or 3-step ratio tables to make complex comparisons involving multi-currency chains and international best buys.
Students will solve rich, non-routine problems that mix direct, inverse, exchange rates, recipes, and reverse percentages, identifying the correct mathematical tools to use.
Unit code NP10
NP10
Solve scaling problems involving direct and inverse relationships.