CHALLENGE 13: Subtracting 9 and 11 from double digit numbers
Strategies:
1. To subtract 9, subtract 10 and then add 1.
2. To subtract 11, subtract 10 and then subtract 1 more.
47 - 9 =
60 - 11 =
78 - 9 =
88 - 11 =
35 - 11 =
89 - 11 =
57 - 9 =
43 - 9 =
16 - 11 =
25 - 9 =
86 - 9 =
63 - 11 =
67 - 11 =
27 - 11 =
57 - 9 =
16 - 9 =
52 - 11 =
23 - 11 =
92 - 9 =
47 - 11 =
55 - 9 =
78 - 11 =
55 - 9 =
97 - 11 =
27 - 11 =
28 - 9 =
66 - 9 =
84 - 9 =
55 - 9 =
23 - 9 =
30 - 11 =
35 - 11 =
75 - 11 =
23 - 9 =
88 - 11 =
45 - 9 =
13 - 9 =
27 - 11 =
81 - 9 =
62 - 11 =
35 - 9 =
19 - 11 =
15 - 9 =
16 - 9 =
74 - 11 =
34 - 11 =
67 - 11 =
56 - 11 =