Stone age people in Mexico and California ground up kernels of corn, acorns and seeds in shallow depressions in granite boulders (called a metate). These items are very common in the San Diego foothills, as the native American tribes were using them until only one or two hundred years ago.
Eventually the big boulder got carved down into a tray for portability. With feet so your back wouldn't hurt so much from leaning over it. it Then it became a bowl so things wouldn't fly out so easily. The round stone got a handle so you wouldn't be bashing your fingertips all the time.
Now known as a metate y mano or mortar and pestle, variations of this tool are used in chemistry, medicine and cooking.
TV chef Jamie Oliver has become famous for his generous use of herbs, spices and olive oil. He uses a mortar and pestle all the time. For those who don't want the weight and trouble of a mortar, the personal electric spice grinder is now a favorite tool. You can grind spices or coffee beans or whatever you like. Just remember you need to be within reach of an electrical power outlet.
I know you are wondering when I will get around the the math! Now.
Let's draw some parallels between this history lesson about cooking, and math. In the beginning, we started with tally marks. Then we drew numbers with our fingers in sand or mud ...
and when we needed to move the numbers we cut out a tablet of clay and handed it to someone else.
read about the Tally Stick) that we could share with other people.
It was a nuisance to edit these carved numbers, until some bright thinker put sliding markers on sticks and called it an abacus: