OK.2.2. Number Sense and Operation - The student will use numbers and number relationships to acquire basic facts and will compute with whole numbers less than 100.
2.2.2. Number Operations
2.2.2.a. Demonstrate fluency (i.e., memorize and apply) with basic addition facts to make a maximum sum of 18 and the associated subtraction facts (e.g., 15+3=18 and 18-3=15).
2.2.2.b. Use strategies to estimation and solve sums and differences (e.g., compose, decompose and regroup numbers, use knowledge of 10 to estimate quantities and sums .)