Answer:
21.78
Explanation:
The fraction 4/5 has the decimal value 0.8. The mixed number 25 4/5 is equivalent to the decimal number 25.8.
When you do the subtraction, you may want to add a trailing zero to 25.8 to make the same number of decimal places as 4.02. Then you have ...
25.80 -4.02
and subtraction proceeds in the normal way.
25.80 -4.02 = 21.78
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It is useful to memorize the decimal equivalents of fractions with denominators of 10 or less. It is also helpful to note that denominators of 2 and 5 and their multiples can be translated directly to fractions with denominators of 10 or other powers of 10:
![(4)/(5)=(4\cdot 2)/(5\cdot 2)=(8)/(10)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pp554oa5osj5let7io74udfrt386sicnqv.png)