The number 0.81 is less than 0.84, 0.80 is less than 0.81, and 0.639 is less than 0.80. Then it is represented as 0.639 < 0.80 < 0.81 < 0.84.
It is the order of the numbers in which a smaller number comes first and then followed by the next number and then the last number will be the biggest one.
The numbers are given below.
0.84, 0.8, 0.81, 0.639
Then arrange in ascending order
0.639 < 0.80 < 0.81 < 0.84
More about the ascending order link is given below.
https://brainly.com/question/320500
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