Yesterday's slightly more difficult little problem
Compared with yesterday's question, the difficulty lies in the uncertainty of some numbers, through simple reasoning, can not come up to know, this number must be so-and-so, must need simple verification.
First, find a breakthrough, the breakthrough of this problem is in a.
This is a four-digit × 4, and the number is still a four-digit problem, so it is impossible for a to ≥ 3, because if ≥ 3, the number will become five digits. Then we determine a = 1 or 2, and then look at it, because a is still a single digit in the number, is obtained by d×4, we have common sense, any number × 4, the number will never appear odd, can only be even, so, exclude 1, a = 2.
Second, determine a = 2, then d, with a range, 2×4 = 8, or if there is a carry, it may also be 9, so d = 8 or 9, the verification begins, if d = 8, then d ×4 = 32, the mantissa is 2, and the title is consistent, if d = 9, then d×4 = 36, the mantissa will be 6, and we have determined that the a = 2 in the number, so exclude 9, d = 8.
Third, determine d = 8, indicating that the hundred will not go to the thousandth bit here, so b will not be too large, and it cannot be ≥ 3, because it is not the highest bit, so it may be 0, 1, 2. Since we have determined that d = 8, so the number of digits carried to ten is 3, then b is actually the result of the number +3 equal to c×4, in the same way, c×4 can never be odd, then +3 can never be even, so exclude 0, 2, b = 1.
Fourth, the last look at c, has been more obvious, because b = 1, c×4 + 3 of the number of mantissa must be 1, that is to say, the mantissa of the c×4 number must be 8, then we know that 2×4 = 8, 7×4 = 28, two possibilities, c = 2 or 7, first look at if c = 2, 2×4 + 3 = 11, the hundred bits of this carry 1, b× 4 = 1×4 = 4, and then +1 = 5, second, if we just assume that c = 2, obviously can not verify, then verify 7, 7×4 + 3 = 31, 100 carry 3, exactly 4 + 3 = 7, c This is directly opposite [cute] so c = 7
Only the text is really difficult to describe, but simple video is sometimes afraid to talk about not quite clear, even with the pen with the drawing, I hope you can understand [shy] [shy] [shy]
Today we leave a simple one
family
My home
Love my home
+ I love my home
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