Question 1192796
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The other tutor works these problems of finding (A-B) mod C by first performing the indicated subtractions and then finding the mod C equivalents of the results by adding or subtracting multiples of C until the result is 0 < n < C.<br>
While that is a valid method, in most cases the work is easier if you use the features of modular arithmetic.<br>
7) (48-15) mod 10 = (48) mod 10 - (15) mod 10 = 8-5 = 3<br>
8) (24-31) mod 5 = (24) mod 5 - (31) mod 5= 4-1 = 3<br>
9) (62-85) mod 12 = (62) mod 12 - (85) mod 12 = 2-1 = 1<br>