|
Here's how we're going to do it:

Now, remember, that's really
90
= 80
+ 10!
Now, here's the key to this whole trick:
|
A
1 in the tens
stripe is 10...
and that's the same as 10 ones! |
< It's just
like swapping a $10 bill for ten $1 bills! >

Now, add the 10
and the 2
in the ones stripe:

Now, we'll finish it off quick!
Subtract the ones... Then, subtract
the
tens...
Go to the next page for another one... It's
going to feel a LOT easier the second time!
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