Regrouping
12 + 18 =
30
12 + 13 =
25
26 + 53 =(estimate the addends to the nearest 10 and then add)
30 + 50 = 80
Actual sum: 79
In the school play, Clara sees 35 singers and 36 dancers. How many children does Clara see on the stage in all?
71
27 + 25 + 31 =
83
25 + 25 =
50
71 + 5 =
76
12 + 27 =(estimate the addends to the nearest 10 and then add)
10 + 30 =40 40
Actual sum: 39
Al reads 17 stories about far away places to visit. Sandy reads 12 more stories than Al. How many stories do they read in all?
29 stories
18 + 9 + 71 =
98
68 + 18 =
86
82 + 17 =
99
77 + 21 =(estimate the addends to the nearest 10 and then add)
80 + 20 =100
Actual sum: 98
Todd collects 27 shells at the beach. Nora and Joe collect 26 shells each. How many shells do Todd, Nora, and Joe collect all together?
79 shells
34 + 9 + 15 + 28 =
86
54 + 29 =
83
50 + 29 =
79
52 + 45 =(estimate the addends to the nearest 10 and then add)
50 + 50 =100
Actual sum: 97
There were 48 children on a boat ride. A dozen more children join them. How many children are there on the boat ride now?
60 children
28 + 49 + 13 + 7 =
97
11 + (9 + ( 3 + 5) 2 ) - 7 =
77
5x - 4y = -23
-5x + 9y = 8
(-7, -3)
18 + ( 8 x (10 - 5) 2 ) + 5 =
223
7x - 5y = -24
-9x + 5y = 18
(3, 9)
566