calculo mental 4º

1

2

45 + 30 = 75

4 + 3 = 75

412 + 300 = 712

3

43 - 30 = 13

4 - 3 = 13539 - 300 = 239

4

413 + 30 = 443

1 + 3 = 4

4213 + 30 = 4243

5

463 - 30 = 433

6 - 3 = 3

4253 - 30 = 4223

6

27 x 10 = 270

46 x 100 = 4600

65 x 1000 = 65000

7

2 x 60 = 120

6 x 200 = 1200

5 x 1000 = 5000

8

20 x 60 = 1200

60 x 200 = 12000

50 x 1000 = 50000

9

43 x 2 =86

14 x 20 =280

10

20 10 = 2

2 1 = 1

300 10 = 30

11

200 100 = 2

2 1 = 1

3000 1000 = 3

12

20 2 = 10

2 1 = 1

246 2= 123

13

164 + 11 = 175

164 + (10+1) = 175

3216 + 11 = 3327

14

16 + 9 = 2516 + (+10-1) = 25

316 + 9 = 325

15

16 - 11 = 5

16 - -10-1) = 27

16

16 - 9 = 716 - (-10+1) = 27

316 - 9 = 307

17

23 + 36 =59

(2+3)=5 (3+6)=9

18

37 + 53 =90

(3+5)=8+1 (7+3)=10

19

16 + 21 = 27

16 + (20+1) = 27

20

16 + 31 = 47

16 + (30+1) = 47

21

16 + 41 = 57

16 + (40+1) = 57

22

16 + 19 = 35

16 + (20-1) = 35

23

16 + 29 = 45

16 + (30-1) = 45

24

16 + 39 = 55

16 + (40-1) = 55

25

56 - 21 = 35

56 - (20-1) = 35366 - 21 = 345

26

56 - 31 = 25

56 - (30-1) = 25366 - 31 = 335

27

56 - 19 = 37

56 - (20+1) = 37366 - 19 = 347

28

856 + 101 = 957

856 +100 +1 = 957

29

856 + 201 = 1057

856 +200 +1 = 1057

30

856 + 301 = 1157

856 +300 +1 = 1157

31

246 - 99 = 147246 - (100+1) = 147

32

646 - 199 = 447

646 - (-200+1) = 447

33

1446 - 299 = 1147

1446 - (-300+1) = 1147