A book with 53 pages numbered 1 to 53 has its pages renumbered in reverse, from 53 to 1. For how many pages do the new page number and old page number share the same units digit?
Here are the numbers reversed so that you can see for yourself:
1 53
2 52........................1
3 51
4 50
5 49
6 48
7 47........................2
8 46
9 45
10 44
11 43
12 42.......................3
13 41
14 40
15 39
16 38
17 37........................4
18 36
19 35
20 34
21 33
22 32.........................5
23 31
24 30
25 29
26 28
27 27..........................6
28 26
29 25
30 24
31 23
32 22..........................7
33 21
34 20
35 19
36 18
37 17..........................8
38 16
39 15
40 14
41 13
42 12...........................9
43 11
44 10
45 9
46 8
47 7..........................10
48 6
49 5
50 4
51 3
52 2...........................11
53 1
