Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Math (Comp. Sci) > Mental Arithmetic (Rules 1-5) > Flashcards

Mental Arithmetic (Rules 1-5) Flashcards

Multiplication

1
Q

What is Rule 1?

A

If the first digits are the same and the second digits are both 5s then you add 1 to the first digit in the first row and then multiply.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Rule 2?

A

If first digits are the same numbers and the second digits add up to ten then you add 1 to the first digit in the first row and then multiple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Rule 3?

A

If the first digits add up to ten and the second set of digits are the same then you multiply the last row and place the answer, then multiply the first digits and add one of the numbers in the second row of digits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is rule 4?

A

Difference of Squares. a^2 - b^2 = (a-b) (a+b) If the difference between two numbers is equal then square the number that is directly between them MINUS how far they are apart^2 SO: (29)(31) = (30 -1)(30+1) 30^2 - 1^2 900 - 1 = 899

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is rule 5?

A

Any 2-digit number times 11 will equal the first digit in the 2 digit number, the second digit = first digit + second digit of the first two digit number, third digit equals the second digit in the 2 digit number. SO 43 x 11 = 4,(7 (4+3)),3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

(45) (65)

A

2925

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

(55) (55)

A

3025

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

(14) (94)

A

1316

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

(24) (84)

A

2016

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

(34) (74)

A

2516

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

(44) (64)

A

2816

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

(13) (93)

A

1209

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

(23) (83)

A

1909

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

(33) (73)

A

2409

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

(43) (63)

A

2709

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

(12) (92)

A

1104

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

(22) (82)

A

1804

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

(32) (72)

A

2304

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

(42) (62)

A

2604

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

(11) (91)

A

1001

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

(21) (81)

A

1701

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

(31) (71)

A

2201

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

(41) (61)

A

2501

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

(51) (51)

A

2601

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

(52) (52)

A

2704

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

(53) (53)

A

2809

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

(54) (54)

A

2916

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

(55) (55)

A

3025

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

(56) (56)

A

3136

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

(57) (57)

A

3249

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

(58) (58)

A

3364

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

(59) (59)

A

3481

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

(16) (96)

A

1536

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

(26) (86)

A

2236

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

(36) (76)

A

2736

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

(46) (66)

A

3036

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

(56) (56)

A

3136

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

(17) (97)

A

1649

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

(27) (87)

A

2349

40
Q

(37) (77)

A

2849

41
Q

(47) (67)

A

3149

42
Q

(57) (57)

A

3249

43
Q

(18) (98)

A

1764

44
Q

(28) (88)

A

2464

45
Q

(38) (78)

A

2964

46
Q

(48) (68)

A

3264

47
Q

(58) (58)

A

3364

48
Q

(19) (99)

A

1881

49
Q

(29) (89)

A

2581

50
Q

(39) (79)

A

3081

51
Q

(59) (59)

A

3481

52
Q

(19) (21)

A

399

53
Q

(29) (31)

A

899

54
Q

(39) (41)

A

1599

55
Q

(49) (51)

A

2499

56
Q

(59) (61)

A

1199

57
Q

(69) (71)

A

4899

58
Q

(79) (81)

A

6399

59
Q

(89) (91)

A

8099

60
Q

(18) (22)

A

396

61
Q

(28) (32)

A

896

62
Q

(38) (42)

A

1596

63
Q

(48) (52)

A

2496

64
Q

(58) (62)

A

3596

65
Q

(78) (82)

A

6396

66
Q

(88) (92)

A

8096

67
Q

(11) (52)

A

572

68
Q

(17) (23)

A

391

69
Q

(27) (33)

A

891

70
Q

(15) (25)

A

375

71
Q

(25) (35)

A

875

72
Q

(35) (45)

A

1575

73
Q

(45) (55)

A

2475

74
Q

(55) (65)

A

3575

75
Q

(65) (75)

A

4875

76
Q

(94) (96)

A

9024

77
Q

(11) (32)

A

352

78
Q

(25) (25)

A

625

79
Q

(35) (35)

A

1225

80
Q

(38) (32)

A

1216

81
Q

(47) (43)

A

2021

82
Q

(43) (63)

A

2709

83
Q

(56) (56)

A

3136

84
Q

(47) (67)

A

3149

85
Q

(82) (22)

A

1804

86
Q

(69) (71)

A

4898

87
Q

(58) (62)

A

3596

88
Q

(18) (22)

A

396

89
Q

(43) (11)

A

473

90
Q

(32) (11)

A

352

91
Q

(69) (61)

A

4209

92
Q

(74) (76)

A

5624

93
Q

(29) (31)

A

899

94
Q

(49) (51)

A

2499

95
Q

(39) (41)

A

1599

Math (Comp. Sci) (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions