Washington State Standards for Mathematics: Grade 2

WA.2.1. Core Content: Place value and the base ten system (Numbers) Students refine their understanding of the base ten number system and use place value concepts of ones, tens, and hundreds to understand number relationships. They become fluent in writing and renaming numbers in a variety of ways. This fluency, combined with the understanding of place value, is a strong foundation for learning how to add and subtract two-digit numbers.

2.1.A. Count by tens or hundreds forward and backward from 1 to 1,000, starting at any number.

2.1.B. Connect place value models with their numerical equivalents to 1,000.

2.1.C. Identify the ones, tens, and hundreds place in a number and the digits occupying them.

2.1.D. Write three-digit numbers in expanded form.

2.1.E. Group three-digit numbers into hundreds, tens, and ones in more than one way.

2.1.F. Compare and order numbers from 0 to 1,000.

WA.2.2. Core Content: Addition and subtraction (Operations, Geometry/Measurement, Algebra) Students focus on what it means to add and subtract as they become fluent with single-digit addition and subtraction facts and develop addition and subtraction procedures for two-digit numbers. Students make sense of these procedures by building on what they know about place value and number relationships and by putting together or taking apart sets of objects. This is students' first time to deal formally with step-by-step procedures (algorithms) - an important component of mathematics where a generalizable technique can be used in many similar situations. Students begin to use estimation to determine if their answers are reasonable.

2.2.A. Quickly recall basic addition facts and related subtraction facts for sums through 20.

2.2.B. Solve addition and subtraction word problems that involve joining, separating, and comparing and verify the solution.

2.2.C. Add and subtract two-digit numbers efficiently and accurately using a procedure that works with all two-digit numbers and explain why the procedure works.

2.2.D. Add and subtract two-digit numbers mentally and explain the strategies used.

2.2.E. Estimate sums and differences.

2.2.F. Create and state a rule for patterns that can be generated by addition and extend the pattern.

2.2.G. Solve equations in which the unknown number appears in a variety of positions.

2.2.H. Name each standard U.S. coin, write its value using the dollar sign and the cents sign, and name combinations of other coins with the same total value.

2.2.I. Determine the value of a collection of coins totaling less than $1.00.

WA.2.3. Core Content: Measurement (Geometry/Measurement) Students understand the process of measuring length and progress from measuring length with objects such as toothpicks or craft sticks to the more practical skill of measuring length with standard units and tools such as rulers, tape measures, or meter sticks. As students are well acquainted with two-digit numbers by this point, they tell time on different types of clocks.

2.3.A. Identify objects that represent or approximate standard units and use them to measure length.

2.3.B. Estimate length using metric and U.S. customary units.

2.3.C. Measure length to the nearest whole unit in both metric and U.S. customary units.

2.3.D. Describe the relative size among minutes, hours, days, weeks, months, and years.

2.3.E. Use both analog and digital clocks to tell time to the minute.

WA.2.4. Additional Key Content (Numbers, Operations, Geometry/Measurement, Data/Statistics/Probability) Students make predictions and answer questions about data as they apply their growing understanding of numbers and the operations of addition and subtraction. They extend their spatial understanding of Core Content in geometry developed in kindergarten and grade one by solving problems involving two- and three-dimensional geometric figures. Students are introduced to a few critical concepts that will become Core Content in grade three. Specifically, they begin to work with multiplication and division and learn what a fraction is.

2.4.A. Solve problems involving properties of two- and three-dimensional figures.

2.4.B. Collect, organize, represent, and interpret data in bar graphs and picture graphs.

2.4.C. Model and describe multiplication situations in which sets of equal size are joined.

2.4.D. Model and describe division situations in which sets are separated into equal parts.

2.4.E. Interpret a fraction as a number of equal parts of a whole or a set.

WA.2.5. Core Processes: Reasoning, problem solving, and communication - Students further develop the concept that doing mathematics involves solving problems and talking about what they did to solve those problems. Second-grade problems emphasize addition and subtraction with increasingly large numbers, measurement, and early concepts of multiplication and division. Students communicate their mathematical thinking and make increasingly more convincing mathematical arguments. Students participate in mathematical discussions involving questions like ''How did you get that?''; ''Why did you use that strategy?''; and ''Why is that true?'' Students continue to build their mathematical vocabulary as they use correct mathematical language appropriate to grade two when discussing and refining solutions to problems.

2.5.A. Identify the question(s) asked in a problem and any other questions that need to be answered in order to solve the problem.

2.5.B. Identify the given information that can be used to solve a problem.

2.5.C. Recognize when additional information is required to solve a problem.

2.5.D. Select from a variety of problem-solving strategies and use one or more strategies to solve a problem.

2.5.E. Identify the answer(s) to the question(s) in a problem.

2.5.F. Describe how a problem was solved.

2.5.G. Determine whether a solution to a problem is reasonable.