LAC 28:CXLII.705. Algebraic Reasoning

A. Represent and solve problems involving addition and subtraction. 1. Use addition and subtraction within 100 to solve one- and two-step real-world mathematical tasks involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions for one or two operations. a. Represent these situations using models and equations, elevating the concrete-representation-abstract instructional framework. 2. Add and subtract up to 1000 using concrete models or drawings and strategies based on place value, properties of operations, and/or the part:whole relationship between addition and subtraction. a. Understand that in adding or subtracting three-digit numbers, add or subtract hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds. b. Justify the reasoning used when choosing the model or strategy to compute with a written explanation. B. Work with equal groups of objects to gain foundations for multiplication. 1. Determine whether a group of objects up to 20 has an odd or even number of members. a. Represent these situations by paring objects or counting them by 2s. b. Write an equation to express an even number as a sum of equal addends. 2. Use addition to find the total number of objects arranged in equal groups and rectangular arrays with up to 5 rows and up to 5 columns. a. Write an equation to express the total as a sum of equal addends.