I always ask the students “What sound does a ghost make?” When they say “ooooo,” I spookily ask them if they think it’s a coincidence ghost zeros spell oooooo.
Ghost Zeros Exist- In Decimals that is!
Every fall, as the air gets crisp and the days grow shorter, a nightmare befalls teachers across the country. Every teacher knows how difficult it is for students to understand that adding zeros as place holders for the tenths, hundredths, or thousandths place doesn’t change the value at all. But often times, doing so makes the numbers easier to work with!
I too have been frustrated at how difficult the concept can be for some students. After I started teaching students the “ghost decimal” strategy, the learning became less of a trick and more of a treat!
So what is a “Ghost Decimal?”
A ghost decimal is simply any decimal place that holds a trailing zero. Often, ghost decimal points and ghost zeros are invisible.
Students must understand that every number has a decimal point whether you can see it or not and an unlimited number of zeros can follow that decimal point.
Using Ghost Zeros in Addition and Subtraction
Learning when to add ghost zeros and how many ghost zeros to add is an important skill for students as they begin adding and subtracting decimals.
Students seem to need the most help when they are subtracting a decimal from a whole number, such as 20 – 13.59. An easy practice is to get in the habit of simply adding a ghost decimal point and two ghost zeros to the number before lining up the decimal point and subtracting.
Other times the two numbers being added do not have the same number of decimal places, such as 3.1 + 5.98. In this case, the students can add one ghost zero to 3.1 and then do the math regularly.
Using Ghost Zeros in Division
Great for Comparing Fractions!
As students get to higher grade levels, ghost zeros come in handy when they learn to divide with decimals or convert fractions to decimals. When I was in school, I didn’t love working with fractions. As often as possible, whether I was adding fractional values or fractions with unlike denominators, or whether I was comparing different fractions, I liked to convert them into decimals first. It just seemed easier to me!
Make Practice Spooky Fun
In addition to the craftivities included in this week’s free resources, there are also practice worksheets! To make it a little more fun, cut the worksheet into individual problems and stuff them into a white balloon before inflating it. Turn off the lights and have students go on a ghost hunt. Once everyone has found their “ghost”, they can pop them and solve the problems!
Click the pic for some inexpensive white (Amazon PRIME!!!) balloons! Just use a magic marker to turn them into ghosts!
Try teaching ghost decimals in your class! It’s an easy concept that sticks! Plus, it helps to eliminate classic mistakes that students make as they begin working with decimals.