Question

What is then common difference in the arithmetic sequence 1, 1.25, 1.5, 1.75

Answer 1

a2-a1=1.25-1=0.25

a3-a2=1.5-1.25=0.25

a4-a3=1.75-1.5=0.25

a5-a4=2-1.75=0.25

a6-a5=2.25-2=0.25

As you can see, the difference in this sequence is constant and is equal to 0.25,

Answer 2

Take any two consecutive numbers in the listed sequence. Subtract them.

1.25 - 1 = 0.25

1.5 - 1.25 = 0.25

1.75 - 1.5 = 0.25

The common difference is 0.25