Oregon Academic Content Standards
OR.3.NBT. Number and Operations in Base Ten
D. Solve problems involving the four operations, and identify and explain patterns in arithmetic.
3.OA.8. Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. (This standard is limited to problems posed with whole numbers and having whole number answers; students should know how to perform operations in the conventional order when there are no parentheses to specify a particular order (Order of Operations).)
E. Use place value understanding and properties of operations to perform multi-digit arithmetic. (A range of algorithms may be used.)
3.NBT.2. Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.