3 Sig Fig Illustrations That Make the Concept Stick

Students don’t have a clear picture of what each type of zero looks like. In fact, when you grade sig fig homework it feels like they pulled the answers out of a hat.

Students know there are rules, but the rules blur together. Especially, when students look at a number with multiple zeros in it.

In class, half your students might get it. But when they come back to class after trying the homework? It’s more chaotic than a class party with a sub the day before school gets out.

How do you clarify this topic and avoid the chaos?

You cartoonify the zeros and sig figs. Then students get a clear picture of zeros and significant figures. If you make the images memorable enough, they can recall the examples anytime they get stuck. Like a quiz they stared at the review for 3 hours studied for).

If you make this basic concept memorable, it will make teaching more advanced topics easier.

After you cartoonify the zeros, pair the illustrations with this easy to use worksheet.

Make Sandwiched Zeros…Sandwiched​

Nothing resonates with an insatiable student appetite like a sandwich. So show sandwiched zeros.

There are other ways to refer to these zeros (captive zeros, trapped zeros). But I try to avoid words with hostage connotations in class.

Never give students a reason to refer to you as the overlord or captor. They'll take it.

You can even take the analogy further and explain that sandwiched zeros are like roast beef in a sandwich. The roast is significant, stuck in the middle, and without it, it would be a tomato sandwich.

No one likes a tomato sandwich (Except for grandma).

Make Leading Zeros an Ex-Girlfriend

Want to be relatable to students? Tell them that leading zeros will lead them on and not be significant...like that boy/girl that they dated last spring.

You’ll get a bunch of snickers for that comment.

And you know what? They will remember that leading zeros look significant, but they are just leading you on.

Take this a step further and explain to students this is because leading zeros don't contribute to how specific a number is.

Make Trailing Zeros Trail Off

​Trailing zeros are the worst for students. Why? Because the rules we've been given for years don't split up trailing zeros. They smush the rules about trailing zeros together and it makes students' brains explode.

The solution to non-exploding heads is to create two rules. The first one is for trailing zeros without decimals.

So tell your students to look at the decimal. If the zeros are trailing off after the decimal they are zeros that aren't significant.

Tell your students they can remember this because when someone trails off in a sentence they are not sure of what to say..

Which is perfect for these zeros because sometime they are significant and sometimes they are insignificant.

...But Also Lead the Trail

The second trailing zeros rule is simple too. If the trailing zero doesn't have a decimal, then they are zeros that aren't significant.

Tell students it's because the number was guestimated, and not specifically measured.

(Read this post to see how huge that word is to making this lesson easy)

Make the Rules Stick with Students

To students, rules are just a highlighted part of the textbook. Unless they can practice them.

Which is why this worksheet was made for this lesson (and to make teaching this easier for you.)

Take these illustrations and pair them with this worksheet for a memorable lesson that students will be able to complete at any time of the year.

(Yes, that means not having to reteach it in a month and a half.)