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And want extra credit for you.

     But, I just don't know,

     How you can go

Beyond that which already you can't do.

could be substituted

for 'math' in this limerick.)

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To subtract from the price of the rice.

     It is 20% off,

     And equals, I scoff,

80 % of the price.

such as 80% and 20%,  60%

and 40%,  40% and 60%,  70%

and 30%, and so forth. 

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In one you see nothing at all.

     The other a zero,

     Quite real and so,

Not ‘nothing’ ; it’s a number after all!

0

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Multiply 15,873.

    And again times 7,

    The product to leaven,

Your pick, repeating 6 times you'll see.

then you can work backwards

and choose numbers that will

result in your picked number

repeating as often as you like.

The power's not 4, that's true.

     The exponent is 4,

     With base 2, what's more,

16 is the 4 th power of 2 .

2 ⁴

Divide by 1 just for fun.

     Add 0 to this,

     And what don't you miss,

X with 'invisible' notation.

X