Subtraction Quiz

Subtraction Quiz #1


We had a Math quiz today. We've been working on problem solving using subtraction. We have also talked heavily about how one can use addition to check their subtraction. The boys and girls have learned that when we are asked to "Explain our thinking" or, how do you know you're right?  They can refer back to the "Checking by adding" method.  

Have a look at the attached quiz. Here is what a level four answer looks like: 

Mrs. Linse has 25 more points than Mrs. Mihalides.  I know this because I used addition to help me and I flipped the question around so it was 25+46 and it equaled 71. That's how I know I am right. 

We've talked a lot about not telling a story when explaining one's thinking. For example, "First, I subtracted the ones column, then I borrowed ten from the tens column"...etc.  This does not justify the answer, it simply tells the process. We will continue our discussion about how to explain one's thinking but when the quiz comes home, it would be beneficial for families to review this as well. 

Parents are asked to continue to practice problems such as the one posed in the quiz with their children at home.