1800:
Joseph Marie Jacquard teaches a loom to read punch cards, creating the first heavily multi-threaded processing unit. His invention was fiercely opposed by the silk-weavers who expected the birth...
Integer (Z)= ...-3,-2,-1,0,1,2 3,4...
A.If you add two integers you will get ineger
Like 4 + 5 = 9
Integer+integer=integer
So , you can say integers are closed under addition....
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