The 5s row
Let's hunt for a pattern in the five times table. We'll list a few rows and look for something that repeats.
Five times one is five.
Five times two is ten.
Five times three is fifteen.
Five times four is twenty.
Five times five is twenty-five.
Now zoom in on the ones digits — the last digit of each answer.
Five, zero, five, zero, five! The ones digit flips between five and zero.
Each row we add five more. Two fives make ten, so the ones digit lands back on zero, then jumps up to five again.
Let's test it. Five times six is thirty — and look, it ends in zero. The pattern keeps going.
Any number times five ends in zero or five. That's the pattern of the fives!