(a)
Repeat-subtraction is a method of subtracting an equal number of items from a larger group. In this case, we have to form 18 groups and subtract 18 items from 585 until we get zero or closer.
585-18 = 567
567-18 = 549
549-18 = 531
531-18 = 513
513-18 = 495
495-18 = 477
477-18 = 459
459-18 = 441
411-18 = 423
423-18 = 405
405-18 = 387
387-18 = 369
369-18 = 351
351-18 = 333
333-18 = 315
315-18 = 297
297-18 = 279
279-18 = 261
261-18 = 243
243-18 = 225
225-18 = 207
207-18 = 189
189-18 = 171
171-18 = 153
153-18 = 135
135-18 = 117
117-18 = 99
99-18 = 81
81-18 = 63
63-18 = 45
45-18 = 27
27-18 = 9
As you can observe, we can form 32 groups, which means the quotient is 32, and the remainder is 9.
Now, we divide use the standard algorithm
Now, we repeat the process for b and c.
(b)
Subtracting 22 from 561, we get 25 formed groups in total using the repeated-subtraction method. Then, using the standard method, we get
So, the remainder is 11 and the quotient is 25.
(c)
Subtracting 97 from 1000, we get 10 groups. Then,