05 820 897

### Question 1

Performing addition and subtraction with decimals in a $1 \leftarrow 10$ machine is no different from performing addition and subtraction in a $1 \leftarrow 10$ machine without decimals.

For example, here is a picture of $22.37+5.841$.

We see the answer $2|7.11|11|1$. Just add left to right and don’t worry about explosions!

Now with explosions we obtain an answer that society understand. We get $28.211$. (Check this!)
And here is $10.23-4.57$.

We see the answer, after some annihilations, as $1|-4.-3|-4$. (Do you see this?)

Now with some unexplosions, we can fix up this answer for society to read. We get $10.23-4.57=5.66$.

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

### Question 2

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

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

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