You can't because math is a subject involving erasing LOTS of it, even if you use erasable pen its considered better to use a pencil..... :)
A book, a pencil, a pen, and mostly, a brain.
A pen for an animal enclosure could have a mass of 32 kg but a pen with which to write, no.
Pen and paper.
by pencil or pen
you write with a pen
you put your pen to your paper and write troll
you cant write under water
Where you write with a pen.
No, it is not illegal to write in red pen.
Yes, you can use a blue pen to write a check.
a space pen
Well the ink comes out of the pen and that goes on the paper and if you are not an idiot you can write words.
I don't see why you would not be able to write with a pen in space. Pens operate on the principle of capillary attraction, and that is not affected by gravity or the absence of gravity. The only issue I can see is that if you attempt to use a pen in a vacuum, any air bubbles contained in the ink would expand, and the heat of your hand might make the ink boil.
with a pen
to write
the verb (action) is write
Blue Pen or Black Pen