RS1 Level E, Lesson 59: Decimals

We ran across something quite interesting today. RightStart Mathematics Level E, Lesson 59 is a Review and Practice. As shown below, the child is asked to write the number “10 thousandths”.

Level E Lesson 59 fig 1

The answer is 0.010, which can also be written as 0.01. That threw quite a few people into a tizzy.

Let’s follow this and see why 10 thousandths is written as 0.01…. Consider the following.

7 thousandths is written as:  0.007

8 thousandths is written as:  0.008

9 thousandths is written as:  0.009

Following the pattern, 10 thousandths is written as:  0.010  or  0.01

But isn’t 0.01 called 1 hundredth? Yes. But… but… what??

Alright. Let’s look at this through another lens.

What is this number?  2700  Some will say “27 hundred”. Others will say “two thousand seven hundred”. Who’s right? Both are.

It’s the same with 0.010, aka 0.01, being called “10 thousandths” and “1 hundredth”. The same number can be referred in more than one way. It’s all in the perspective!

Karl Ray, the child who was taking this review quiz, explained it a couple days later to his mother in another way. He said to add .008 and .002 vertically like this:

Level E Lessons 59 fig 3

This way, the pattern of 8 thousandths plus 2 thousandths is obviously 10 thousandths which is also 1 hundredth!

As you can see, Karl got the answer! It was the three adults helping him that got stuck in some archaic and useless rule and needed to dig out. Wish we all were taught with the RightStart™ philosophy!


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