1. Mental Math Day 1

2. Basic Addition
Add and subtract the summands to make this easier! =
? = =
2240

3. 5346 + 445 = ? + 450 = 5341 + 450 = 5741+50 = 5791 More Basic Addition- +
SUMMAND 1
SUMMAND 2

4. You try it! (all techniques)= =
=(1+9)+(8+2)+(7+3)+(6+4)+5
= =45 =
2x45=90

5. Sum all entries - Which is More?1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
100 X 1 2 3 4 5 6 7 8 9 10 12 14 16 18 20 15 21 24 27 30 28 32 36 40 25 35 45 50 42 48 54 60 49 56 63 70 64 72 80 81 90
100

6. SUM All ENTRIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
100

7. Total is 10x55+100x45 1 2 3 4 5 6 7 8 9 10
SUM= 55 11 12 13 14 15 16 17 18 19 20
55+100 21 22 23 24 25 26 27 28 29 30
55+200 31 32 33 34 35 36 37 38 39 40
55+300 41 42 43 44 45 46 47 48 49 50
55+400 51 52 53 54 55 56 57 58 59 60
55+500 61 62 63 64 65 66 67 68 69 70
55+600 71 72 73 74 75 76 77 78 79 80
55+700 81 82 83 84 85 86 87 88 89 90
55+800 91 92 93 94 95 96 97 98 99
100
55+900

8. Total is 10x55+100x45 = = =5050 1 2 3 4 5 6 7 8 9 10
SUM= 55 11 12 13 14 15 16 17 18 19 20
55+100 21 22 23 24 25 26 27 28 29 30
55+200 31 32 33 34 35 36 37 38 39 40
55+300 41 42 43 44 45 46 47 48 49 50
55+400 51 52 53 54 55 56 57 58 59 60
55+500 61 62 63 64 65 66 67 68 69 70
55+600 71 72 73 74 75 76 77 78 79 80
55+700 81 82 83 84 85 86 87 88 89 90
55+800 91 92 93 94 95 96 97 98 99
100
55+900

9. Add up all the numbers in this table
(in your head!) X 1 2 3 4 5 6 7 8 9 10 12 14 16 18 20 15 21 24 27 30 28 32 36 40 25 35 45 50 42 48 54 60 49 56 63 70 64 72 80 81 90
100

10. Sum is 55x =? X 1 2 3 4 5 6 7 8 9 10
SUM=55 55 12 14 16 18 20
2x55 15 21 24 27 30
3x55 28 32 36 40
4x55 25 35 45 50
5x55 42 48 54 60
6x55 49 56 63 70
7x55 64 72 80
8x55 81 90
9x55
100
10x55
55 more

11. Sum is 55x55 + 2x55=? =(50+5)x(50+5)+2x55 =(50x50)+5x50+50x5+5x5+2x55
So we need the total of
2500
250 25
110

12. Sum is 55x55 + 55=? So we need the total of 2500 250 25 110
This is =3135