Five for Friday - EOY Freebie and Cinderella Estimation

 I love teaching estimation. I learned a trick years ago that I teach every year and tweak here and there. I call it the CINDERELLA Estimation Trick. 

But first, let me take a selfie. No wait, I mean, let's freshen up our memories. And this is how I begin the class. I ask them about what Fairy God Mother does to Cinderella. They tell me that she changes her clothes, etc, etc. Then I ask what happens to Fairy God Mother after she changes Cinderella. The answer is she disappears. This leads me into the lesson. 

First up - rounding to the nearest tens. 

Let them know that the place value you want to round to is CINDERELLA. So in this case, the tens digit is cinderella 

56 - the 5 is Cinderella. 

Then I say, the number right behind Cinderella, is Fairy God Mother. Sometimes Fairy God Mother has power and sometimes she doesn't. If she is a 0, 1, 2, 3, 4 - She has no power and can't change Cinderella. If she is 5, 6, 7, 8, 9, then she has power and changes Cinderella into one number higher. 

56 -------> 6 (Fairy God Mother), has power, so she will change Cinderella to one number higher (6). If Fairy God Mother did not have power, Cinderella would stay the same (5). 

Next, Fairy God Mother has to disappear. So I say, she goes, "POOF," and turns into a zero. And we ALL say Poof really loudly every time this happens. 

56 ------> 60. 

43 ------> 40..Fairy God Mother (3)  has no power so she can't change Cinderella. But the fairy goes Poof anyway.

After they get the hang of this, we move on to rounding to the nearest 100. So now Cinderella is the hundreds digit, and the number next to her in the tens digit is Fairy God Mother, and the last number next to Fairy God Mother is the assistant who also disappears with the godmother.

673 <----6 is Cinderella. 7 is Fairy God Mother. 3 is assistant. Fairy God mother has power so she changes the 6 into a 7, then she goes POOF and her assistant goes POOF so 673 <---- 700.

Finally, what if it is a 3 or higher digit number but you want to round to something in the middle. For example - 359 rounded to the nearest tens. 

Now we change the story a little bit. Any number that is in FRONT of Cinderella (the number we want to round to), is the evil step sister(s) and we don't do anything to her (them)
- we leave her alone and write her just the way she is. Then we continue the regular steps of the Cinderella rule for the tens and ones digit. 

So 453 to the nearest tens -----> leave 4 alone (evil step sister), and just write it. Then leave Cinderella  alone (5) because Fairy God Mother doesn't have power (3). So the answer is 450.

Soooo long story LONGER, the kids love this method! They get it, they use it, and they remember it!

 Here is a free End of Year Writing activity..."I Mustache (Moustache) You to Get Ready for (the next) Grade." I've included templates for 1-5th grades and a few mustaches to cut out and put on for a picture. It'll make a great end of year bulletin board display!

 Just a cute moment I captured! 

Moving on...

Pictures stop. Phone is full. That was number 4. 

Why, yes it would be great. Also, it's been the same routine since the beginning of the year. We have a month left. When shall we learn the procedures?? 

Have a great weekend!!


  1. OKay the Cinderella ideal is fabulous! Might have to borrow this!

    A Rocky Top Teacher

    1. Thanks Sarah! The best part is when the whole class is so enthusiastic about saying, "POOF!"

  2. The Cinderella story is so fun! Thanks for the cute idea :)


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