Do I really need to teach that? It’s common sense!

What you think is common sense may not be for your students,.  Remember, you are an adult!  While you may think they should just know certain things and that students will make connections using number sense, it is doubtful that they all will.  Teach even what you believe should be common sense.

Wouldn't you be doing your students a disservice by not drawing their attention to those simple connections that could really help them?

Here are three examples based on my experience in the classroom:

Example #1

When graphing linear equations, students don't typically look at equations such as x = 3, y = 8, and 3x + y = 6 and think about what type of line each will form.

So, they just graph a line somewhere on the grid without considering whether the line should be diagonal, horizontal, or vertical.

Fixing this issue can be as simple as having students predict how a line will look before putting pencil to paper.

• Have them write "horizontal", "vertical" or "diagonal" before graphing.
• Give a quick check for understanding focused on only this topic.
• As you work through examples in class, ask students to predict what type of line to expect before graphing.

I think of this as having an understanding of the "big picture".  Others describe it as common sense.

 

Example #2

Another topic I've noticed that students struggle with is labeling perimeter, area, and volume.  Many of them just don't make the "big picture" connection.  They perform all sorts of contortions to decide how to label an answer.  Some seem to think that the shape determines the labeling.

All they need to know is this:

• All areas are square units (area, surface area, lateral area, base area).
• All volumes are cubic units.
• Anything else is single units (length, base, width, height, perimeter, circumference).

It is not common sense ... teach it!  Every student will not just figure it out.  If so, I would need to be writing this post.  

Example #3

The same goes for positive vs. negative slope.  A positive slope is a line that slants upward from left to right showing an increase.  A negative slope is a line that slants downward from left to right showing a decrease.  Train your students to think about whether the slope will be positive or negative before counting it or graphing a linear equation.

Verbalize the key "big picture" takeaways.

Remember, common sense is not common!