02 824 365
Decimalia
Decimalia
Decimalia

Station  8B
Addition and Subtraction 

Question 1

Performing addition and subtraction with decimals in a 1101 \leftarrow 10 machine is no different from performing addition and subtraction in a 1101 \leftarrow 10 machine without decimals.

For example, here is a picture of 22.37+5.84122.37+5.841.
I8S8B - Image115

We see the answer 27.111112|7.11|11|1. Just add left to right and don’t worry about explosions!
I8S8B - Image117

Now with explosions we obtain an answer that society understand. We get 28.21128.211. (Check this!)
And here is 10.234.5710.23-4.57.
I8S8B - Image120

We see the answer, after some annihilations, as 14.341|-4.-3|-4. (Do you see this?)
I8S8B - Image122

Now with some unexplosions, we can fix up this answer for society to read. We get 10.234.57=5.6610.23-4.57=5.66.
(Check that you follow this.)
I8S8B - Image124

What is 0.05+0.0060.05+0.006?
What is 0.050.0060.05-0.006?
Can you see the answer with dots-and-boxes?

Question 2

Agatha says that computing 0.0348+0.00570.0348+0.0057 is essentially the same work as computing 348+57348+57 in whole numbers. Do you agree?

Percy says that computing 0.0852+0.0370.0852+0.037 is essentially the same work as computing 852+37852+37 in whole numbers. Do you agree?

You can either play with some of the optional stations below or go to the next island!

Decimalia
Vision byPowered by
Contact GMP:
  • The Global Math Project on Twitter
  • The Global Math Project on Facebook
  • Contact The Global Math Project
Contact BM:
  • Buzzmath on Twitter
  • Buzzmath on Facebook
  • Visit Buzzmath's Website
  • Read Buzzmath's blog!