Common Core · High school
HSA-REI.A.1
High school — Explain each step in solving an equation as following from the equality of the previous step.
High school — Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, constructing a viable argument to justify a solution method.
The 2 skills that cover it
- Equations with FractionsClear fractions from an equation by multiplying through by the least common denominator, then solve as usual.Read the lesson →
- Logic & ProofRead a conditional statement, write its converse, inverse and contrapositive, test a claim with a counterexample, and give the reason for every step of a proof.Read the lesson →
What a student should be able to do
- Multiply both sides by the least common denominator to clear fractions.
- Solve equations with fractional coefficients and constants.
- Solve simple proportions as rational equations.
- Check solutions and exclude values that make a denominator zero.
- Identify the hypothesis and conclusion of a conditional statement.
- Write the converse, inverse and contrapositive and decide which are true.
- Use a counterexample, the law of detachment and the law of syllogism to test reasoning.
- Justify each step of an algebraic or geometric proof with a definition, property, postulate or theorem.