COUNTING -
Counting is the most fundamental, universal, and basic thing for learning mathematics, without counting nobody can learn mathematics. Without learning about counting nobody can step forward and can learn about addition, subtraction, multiplication, division even higher mathematics like calculus, algebra, geometry, etc, and no subject you can complete like Physics, Chemistry, History, Geography, Biological science, etc.
In below up to down (vertically) and side by side (parallelly), one to twenty-five (1-25) has been written for your better understanding.
And then, in below up to down (vertically) and side by side (parallelly), one to twenty-five (26-50) has been written for your better understanding.