To do Common Core Math, understand the concepts of the base ten number system. Because Common Core is focused on the concepts rather than the algorithm, draw pictures to visually conceptualize the math problems. Expand numbers into separate place values before adding, subtracting, multiplying or dividing.
To use the Common Core Method to add 45 plus 38, break 45 into 40 plus five and 38 into 30 plus eight. Then add the tens together, 40 plus 30 equals 70. Next add the ones. Five plus eight equals 13. Now combine the two answers to get 83. To use Common Core to subtract 38 from 45, pictorially represent 45 by drawing four sticks for the tens place value and five small circles to represent ones. Next cross out three tens and eight ones. You will have to break one of the tens apart into ones to have enough ones to cross out. You are left with seven ones, which is the answer.
To multiply 45 and 38 using Common Core Math, separate the numbers according to place value and multiply. Multiply the tens, 40 and 30, and get 1200. Then multiply 40 times eight to get 360. Multiply 30 and five to get 150. Add the three products together to get an answer of 1710.