Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 1
Q Question
1
23 + 51 = 23 + 50 + ☐
2
58 + 69 = 50 + 60 + ☐
3
67 + 77 = 67 + 70 + ☐
4
43 + 14 = 43 + 10 + ☐
5
75 + 99 = 70 + 90 + ☐
Answer
Day
Q
1
2
3
4
5
2
Question
80 + 30 = 80 + 30 + ☐
99 + 23 = 90 + 20 + ☐
37 + 11 = 30 + 10 + ☐
35 + 38 = 35 + 30 + ☐
34 + 39 = 30 + 30 + ☐
6
94 + 62 = 94 + 60 + ☐
6
73 + 54 = 70 + 50 + ☐
7
72 + 76 = 70 + 70 + ☐
7
26 + 51 = 26 + 50 + ☐
8
24 + 16 = 24 + 10 + ☐
8
85 + 40 = 80 + 40 + ☐
9
57 + 43 = 57 + 40 + ☐
9
68 + 80 = 68 + 80 + ☐
10
Day
Q
1
2
3
4
5
28 + 78 = 28 + 70 + ☐
10 46 + 56 = 40 + 50 + ☐
Day 3
Q Question
1
45 + 80 = 45 + 80 + ☐
2
95 + 30 = 95 + 30 + ☐
3
74 + 69 = 70 + 60 + ☐
4
21 + 79 = 21 + 70 + ☐
5
15 + 27 = 15 + 20 + ☐
Answer
Answer
4
Question
45 + 80 = 45 + 80 + ☐
95 + 30 = 95 + 30 + ☐
74 + 69 = 70 + 60 + ☐
21 + 79 = 21 + 70 + ☐
Answer
15 + 27 = 15 + 20 + ☐
6
61 + 45 = 60 + 40 + ☐
6
61 + 45 = 60 + 40 + ☐
7
19 + 69 = 10 + 60 + ☐
7
19 + 69 = 10 + 60 + ☐
8
80 + 16 = 80 + 10 + ☐
8
80 + 16 = 80 + 10 + ☐
9
26 + 40 = 26 + 40 + ☐
9
26 + 40 = 26 + 40 + ☐
10
35 + 94 = 30 + 90 + ☐
10
35 + 94 = 30 + 90 + ☐
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED
Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 5
Q Question
1
34 + 74 = 34 + 70 + ☐
2
44 + 90 = 44 + 90 + ☐
3
52 + 79 = 52 + 70 + ☐
4
65 + 58 = 65 + 50 + ☐
5
67 + 10 = 60 + 10 + ☐
Answer
Day
Q
1
2
3
4
5
6
Question
66 + 35 = 60 + 30 + ☐
35 + 40 = 30 + 40 + ☐
53 + 55 = 50 + 50 + ☐
46 + 40 = 40 + 40 + ☐
33 + 60 = 30 + 60 + ☐
6
55 + 88 = 55 + 80 + ☐
6
65 + 23 = 65 + 20 + ☐
7
54 + 55 = 50 + 50 + ☐
7
64 + 35 = 60 + 30 + ☐
8
95 + 89 = 95 + 80 + ☐
8
25 + 23 = 20 + 20 + ☐
9
46 + 79 = 46 + 70 + ☐
9
68 + 90 = 68 + 90 + ☐
10
Day
Q
1
2
3
4
5
95 + 14 = 90 + 10 + ☐
10 83 + 83 = 80 + 80 + ☐
Day 7
Q Question
1
66 + 86 = 60 + 80 + ☐
2
58 + 91 = 58 + 90 + ☐
3
45 + 63 = 40 + 60 + ☐
4
40 + 59 = 40 + 50 + ☐
5
40 + 49 = 40 + 40 + ☐
Answer
Answer
8
Question
18 + 62 = 18 + 60 + ☐
57 + 21 = 50 + 20 + ☐
78 + 64 = 78 + 60 + ☐
74 + 53 = 74 + 50 + ☐
Answer
11 + 16 = 10 + 10 + ☐
6
10 + 38 = 10 + 30 + ☐
6
94 + 44 = 90 + 40 + ☐
7
71 + 49 = 70 + 40 + ☐
7
78 + 76 = 78 + 70 + ☐
8
36 + 16 = 30 + 10 + ☐
8
36 + 26 = 30 + 20 + ☐
9
36 + 56 = 30 + 50 + ☐
9
57 + 21 = 50 + 20 + ☐
10
77 + 92 = 70 + 90 + ☐
10
31 + 14 = 31 + 10 + ☐
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED
Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 9
Q Question
1
18 + 62 = 18 + 60 + ☐
2
57 + 21 = 50 + 20 + ☐
3
78 + 64 = 78 + 60 + ☐
4
74 + 53 = 74 + 50 + ☐
5
11 + 16 = 10 + 10 + ☐
Answer
Day
Q
1
2
3
4
5
10
Question
68 + 65 = 68 + 60 + ☐
53 + 45 = 53 + 40 + ☐
84 + 58 = 84 + 50 + ☐
77 + 78 = 70 + 70 + ☐
Answer
81 + 29 = 81 + 20 + ☐
6
94 + 44 = 90 + 40 + ☐
6
77 + 78 = 70 + 70 + ☐
7
78 + 76 = 78 + 70 + ☐
7
77 + 78 = 70 + 70 + ☐
8
36 + 26 = 30 + 20 + ☐
8
59 + 52 = 59 + 50 + ☐
9
57 + 21 = 50 + 20 + ☐
9
60 + 16 = 60 + 10 + ☐
10
31 + 14 = 31 + 10 + ☐
10
22 + 27 = 20 + 20 + ☐
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED
Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 1
Q Question
1
23 + 51 = 23 + 50 + ☐
2
58 + 69 = 50 + 60 + ☐
3
67 + 77 = 67 + 70 + ☐
4
43 + 14 = 43 + 10 + ☐
5
75 + 99 = 70 + 90 + ☐
2
Question
80 + 30 = 80 + 30 + ☐
99 + 23 = 90 + 20 + ☐
37 + 11 = 30 + 10 + ☐
35 + 38 = 35 + 30 + ☐
Answer
0
12
8
8
14
Day
Q
1
2
3
4
5
Answer
1
17
7
4
34 + 39 = 30 + 30 + ☐
13
6
94 + 62 = 94 + 60 + ☐
2
6
73 + 54 = 70 + 50 + ☐
7
7
72 + 76 = 70 + 70 + ☐
8
7
26 + 51 = 26 + 50 + ☐
1
8
24 + 16 = 24 + 10 + ☐
6
8
85 + 40 = 80 + 40 + ☐
5
9
57 + 43 = 57 + 40 + ☐
3
9
68 + 80 = 68 + 80 + ☐
0
10 46 + 56 = 40 + 50 + ☐
Day 3
Q Question
1
45 + 80 = 45 + 80 + ☐
2
95 + 30 = 95 + 30 + ☐
3
74 + 69 = 70 + 60 + ☐
4
21 + 79 = 21 + 70 + ☐
5
15 + 27 = 15 + 20 + ☐
12
28 + 78 = 28 + 70 + ☐
8
4
Question
45 + 80 = 45 + 80 + ☐
95 + 30 = 95 + 30 + ☐
74 + 69 = 70 + 60 + ☐
21 + 79 = 21 + 70 + ☐
Answer
12
7
2
1
7
10
Day
Q
1
2
3
4
5
15 + 27 = 15 + 20 + ☐
3
6
61 + 45 = 60 + 40 + ☐
6
6
61 + 45 = 60 + 40 + ☐
8
7
19 + 69 = 10 + 60 + ☐
18
7
19 + 69 = 10 + 60 + ☐
8
8
80 + 16 = 80 + 10 + ☐
6
8
80 + 16 = 80 + 10 + ☐
9
9
26 + 40 = 26 + 40 + ☐
0
9
26 + 40 = 26 + 40 + ☐
18
10
35 + 94 = 30 + 90 + ☐
9
10
35 + 94 = 30 + 90 + ☐
9
Answer
0
0
13
9
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED
Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 5
Q Question
1
34 + 74 = 34 + 70 + ☐
2
44 + 90 = 44 + 90 + ☐
3
52 + 79 = 52 + 70 + ☐
4
65 + 58 = 65 + 50 + ☐
5
67 + 10 = 60 + 10 + ☐
6
Question
66 + 35 = 60 + 30 + ☐
35 + 40 = 30 + 40 + ☐
53 + 55 = 50 + 50 + ☐
46 + 40 = 40 + 40 + ☐
Answer
11
5
8
6
7
Day
Q
1
2
3
4
5
Answer
4
0
9
8
33 + 60 = 30 + 60 + ☐
3
6
55 + 88 = 55 + 80 + ☐
8
6
65 + 23 = 65 + 20 + ☐
3
7
54 + 55 = 50 + 50 + ☐
9
7
64 + 35 = 60 + 30 + ☐
9
8
95 + 89 = 95 + 80 + ☐
9
8
25 + 23 = 20 + 20 + ☐
8
9
46 + 79 = 46 + 70 + ☐
9
9
68 + 90 = 68 + 90 + ☐
0
10 83 + 83 = 80 + 80 + ☐
Day 7
Q Question
1
66 + 86 = 60 + 80 + ☐
2
58 + 91 = 58 + 90 + ☐
3
45 + 63 = 40 + 60 + ☐
4
40 + 59 = 40 + 50 + ☐
5
40 + 49 = 40 + 40 + ☐
6
95 + 14 = 90 + 10 + ☐
9
8
Question
18 + 62 = 18 + 60 + ☐
57 + 21 = 50 + 20 + ☐
78 + 64 = 78 + 60 + ☐
74 + 53 = 74 + 50 + ☐
Answer
2
8
4
3
9
10
Day
Q
1
2
3
4
5
11 + 16 = 10 + 10 + ☐
7
6
10 + 38 = 10 + 30 + ☐
8
6
94 + 44 = 90 + 40 + ☐
8
7
71 + 49 = 70 + 40 + ☐
10
7
78 + 76 = 78 + 70 + ☐
6
8
36 + 16 = 30 + 10 + ☐
12
8
36 + 26 = 30 + 20 + ☐
12
9
36 + 56 = 30 + 50 + ☐
12
9
57 + 21 = 50 + 20 + ☐
8
10
77 + 92 = 70 + 90 + ☐
9
10
31 + 14 = 31 + 10 + ☐
4
Answer
12
1
8
9
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED
Equivalent Calculations To Make An Addition Easier
Mental Strategies
Complete the daily exercises to focus on improving this skill.
Day 9
Q Question
1
18 + 62 = 18 + 60 + ☐
2
57 + 21 = 50 + 20 + ☐
3
78 + 64 = 78 + 60 + ☐
4
74 + 53 = 74 + 50 + ☐
5
11 + 16 = 10 + 10 + ☐
10
Question
68 + 65 = 68 + 60 + ☐
53 + 45 = 53 + 40 + ☐
84 + 58 = 84 + 50 + ☐
77 + 78 = 70 + 70 + ☐
Answer
5
5
8
15
7
Day
Q
1
2
3
4
5
Answer
2
8
4
3
81 + 29 = 81 + 20 + ☐
9
6
94 + 44 = 90 + 40 + ☐
8
6
77 + 78 = 70 + 70 + ☐
15
7
78 + 76 = 78 + 70 + ☐
6
7
77 + 78 = 70 + 70 + ☐
15
8
36 + 26 = 30 + 20 + ☐
12
8
59 + 52 = 59 + 50 + ☐
2
9
57 + 21 = 50 + 20 + ☐
8
9
60 + 16 = 60 + 10 + ☐
6
10
31 + 14 = 31 + 10 + ☐
4
10
22 + 27 = 20 + 20 + ☐
9
N U M E R A C Y N I N J A S . O R G
©2015
NUMERACY
NINJAS.
ALL
RIGHTS
RESERVED