CDC (Claim-Data-Commentary)

CDC (Claim-Data-Commentary)

The following is an example of the CDC format that we will use in math this year. There will be one CDC problem per unit. Each unit’s CDC problem will relate to that unit. Each CDC will be worth ten daily points, and CDC assignments must be turned in on or before the due date.

In the claim, restate the question or problem in sentence form and include its solution. The claim is worth one point. If the claim is not written in sentence form or you forget to include the solution, you will not receive your point for the claim. Sentences must be complete, begin with a capital letter, and have the correct ending punctuation.

The data is where you will show your work. Make sure you include all steps. The data is worth five points. Points will be deducted for wrong answers and for not showing all of your steps in a logical, easy to follow order. Highlight or circle your final answer in the data.

When writing your commentary for the CDC problem, many of your sentences should be commands. You are telling someone how to solve the problem. Avoid the word “you.” If you are using the word “you,” you’re probably not writing the sentences as commands. The commentary section is worth four points. Make sure you not only say what you did, but also include why you did it. Do not say, “I used order of operations.” You must explain how you used order of operations to solve this particular problem.

Claim

The expression, , when simplified, is equivalent to

Data

Commentary

To evaluate the expression, , use order of operations. Order of operations states that any calculations involving grouping must be completed first. The expression, , is grouped together using parentheses. It must be calculated first. is the same as When adding two integers with opposite signs, find the difference between the absolute value of the two numbers. The greater absolute value is the minuend. The lesser absolute value is the subtrahend. This gives a difference of 3. The 3 is negative because the 4 was negative, and it had the greater absolute value when compared to the 1. Always keep the sign of the integer with the greater absolute value when adding integers. The expression has been simplified to , but there is still more to do.

In the resulting expression, , the parentheses that remain do not show grouping. They show multiplication. Since there are no grouping or exponents in this expression, move on to multiplication and division. Multiplication and division are inverse operations, so they are done in the same step going left to right. The first multiplication or division in this expression is 12 ÷ 3, which equals 4. Our resulting expression is .

Order of operations states that multiplication must be completed before addition or subtraction. Multiply 4 and –3 to get a product of –12. When multiplying two integers, a positive factor times a negative factor results in a negative product. The resulting expression is .

Now, simplify the expression . Because we are adding integers with opposite signs, and the –12 has a greater absolute value than 2, the sum will be negative. Then, find the difference of 12 and 2, which is 12 – 2. 12 – 2 = 10. Because it was already determined that the answer must be negative, the expression, in simplest form, is –10.