Cum să înveți rapid și ușor tabla înmulțirii

Multiplicare este o operație matematică care poate fi reprezentată ca o sumă de termeni identici.

Principiul general al înmulțirii

De exemplu, a ⋅ b (citit ca „a ori b”) înseamnă că însumăm termenii a, al cărui număr este egal cu b. Rezultatul înmulțirii se numește produs.

exemple:

• 2 ⋅ 6 = 2 + 2 + 2 + 2 + 2 + 2 = 12

  (de șase ori două)

• 5 ⋅ 4 = 5 + 5 + 5 + 5 = 20

  (de patru ori cinci)

• 3 ⋅ 8 = 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 = 24

  (de opt ori trei)

După cum știm, din permutarea locurilor factorilor, produsul nu se schimbă. Pentru exemplele de mai sus, rezultă:

• 6 ⋅ 2 = 6 + 6 = 12

  (de două ori șase)

• 4 ⋅ 5 = 4 + 4 + 4 + 4 + 4 = 20

  (de cinci ori patru)

• 8 ⋅ 3 = 8 + 8 + 8 = 24

  (de trei ori opt)

Beneficii practice

Datorită înmulțirii, puteți reduce semnificativ numărul total de articole de același tip etc. De exemplu, dacă avem 7 pachete, fiecare dintre ele conținând 5 pixuri, atunci numărul total de pixuri se găsește prin înmulțirea acestora. doua numere:

5 ⋅ 7 = 5 + 5 + 5 + 5 + 5 + 5 + 5 = 35

(cinci pixuri de șapte ori)

Înmulțiți cu 0

Rezultatul este întotdeauna zero.

• 0 ⋅ 0 = 0
• 1 ⋅ 0 = 0 ⋅ 1 = 0
• 2 ⋅ 0 = 0 ⋅ 2 = 0 + 0 = 0
• 3 ⋅ 0 = 0 ⋅ 3 = 0 + 0 + 0 = 0
• 4 ⋅ 0 = 0 ⋅ 4 = 0 + 0 + 0 + 0 = 0
• 5 ⋅ 0 = 0 ⋅ 5 = 0 + 0 + 0 + 0 + 0 = 0
• 6 ⋅ 0 = 0 ⋅ 6 = 0 + 0 + 0 + 0 + 0 + 0 = 0
• 7 ⋅ 0 = 0 ⋅ 7 = 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0
• 8 ⋅ 0 = 0 ⋅ 8 = 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0
• 9 ⋅ 0 = 0 ⋅ 9 = 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0
• 10 ⋅ 0 = 0 ⋅ 10 = 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0

Înmulțiți cu 1

Produsul este egal cu un alt multiplicator decât unul.

• 1 ⋅ 1 = 1
• 2 ⋅ 1 = 2 ⋅ 1 = 2
• 3 ⋅ 1 = 3 ⋅ 1 = 3
• 4 ⋅ 1 = 4 ⋅ 1 = 4
• 5 ⋅ 1 = 5 ⋅ 1 = 5
• 6 ⋅ 1 = 6 ⋅ 1 = 6
• 7 ⋅ 1 = 7 ⋅ 1 = 7
• 8 ⋅ 1 = 8 ⋅ 1 = 8
• 9 ⋅ 1 = 9 ⋅ 1 = 9
• 10 ⋅ 1 = 10 ⋅ 1 = 10

Înmulțiți cu 2

Adăugați primul factor la sine.

• 1 ⋅ 2 = 1 + 1 = 2
• 2 ⋅ 2 = 2 + 2 = 4
• 3 ⋅ 2 = 3 + 3 = 6
• 4 ⋅ 2 = 4 + 4 = 8
• 5 ⋅ 2 = 5 + 5 = 10
• 6 ⋅ 2 = 6 + 6 = 12
• 7 ⋅ 2 = 7 + 7 = 14
• 8 ⋅ 2 = 8 + 8 = 16
• 9 ⋅ 2 = 9 + 9 = 18
• 10 ⋅ 2 = 10 + 10 = 20

Înmulțiți cu 3

Înmulțim primul factor cu 2, apoi îl adăugăm la rezultat.

• 1 ⋅ 3 = (1 ⋅ 2) + 1 = 2 + 1 = 3
• 2 ⋅ 3 = (2 ⋅ 2) + 2 = 4 + 2 = 6
• 3 ⋅ 3 = (3 ⋅ 2) + 3 = 6 + 3 = 9
• 4 ⋅ 3 = (4 ⋅ 2) + 4 = 8 + 4 = 12
• 5 ⋅ 3 = (5 ⋅ 2) + 5 = 10 + 5 = 15
• 6 ⋅ 3 = (6 ⋅ 2) + 6 = 12 + 6 = 18
• 7 ⋅ 3 = (7 ⋅ 2) + 7 = 14 + 7 = 21
• 8 ⋅ 3 = (8 ⋅ 2) + 8 = 16 + 8 = 24
• 9 ⋅ 3 = (9 ⋅ 2) + 9 = 18 + 9 = 27
• 10 ⋅ 3 = (10 ⋅ 2) + 10 = 20 + 10 = 30

Înmulțiți cu 4

Adăugăm aceeași sumă la primul factor dublat.

• 1 ⋅ 4 = (1 ⋅ 2) + (1 ⋅ 2) = 2 + 2 = 4
• 2 ⋅ 4 = (2 ⋅ 2) + (2 ⋅ 2) = 4 + 4 = 8
• 3 ⋅ 4 = (3 ⋅ 2) + (3 ⋅ 2) = 6 + 6 = 12
• 4 ⋅ 4 = (4 ⋅ 2) + (4 ⋅ 2) = 8 + 8 = 16
• 5 ⋅ 4 = (5 ⋅ 2) + (5 ⋅ 2) = 10 + 10 = 20
• 6 ⋅ 4 = (6 ⋅ 2) + (6 ⋅ 2) = 12 + 12 = 24
• 7 ⋅ 4 = (7 ⋅ 2) + (7 ⋅ 2) = 14 + 14 = 28
• 8 ⋅ 4 = (8 ⋅ 2) + (8 ⋅ 2) = 16 + 16 = 32
• 9 ⋅ 4 = (9 ⋅ 2) + (9 ⋅ 2) = 18 + 18 = 36
• 10 ⋅ 4 = (10 ⋅ 2) + (10 ⋅ 2) = 20 + 20 = 40

Înmulțiți cu 5

Dacă celălalt multiplicator este un număr par, rezultatul se va termina cu zero, dacă este impar, cu numărul 5.

• 1 ⋅ 5 = 5 ⋅ 1 = 5
• 2 ⋅ 5 = 5 ⋅ 2 = 5 + 5 = 10
• 3 ⋅ 5 = 5 ⋅ 3 = (5 ⋅ 2) + 5 = 15
• 4 ⋅ 5 = 5 ⋅ 4 = (5 ⋅ 2) + (5 ⋅ 2) = 20
• 5 ⋅ 5 = 5 + 5 + 5 + 5 + 5 = 25
• 6 ⋅ 5 = 5 ⋅ 6 = (5 ⋅ 5) + 5 = 30
• 7 ⋅ 5 = 5 ⋅ 7 = 5 + 5 + 5 + 5 + 5 + 5 + 5 = 35
• 8 ⋅ 5 = 5 ⋅ 8 = (5 ⋅ 4) + (5 ⋅ 4) = 40
• 9 ⋅ 5 = 5 ⋅ 9 = (5 ⋅ 10) – 5 = 45
• 10 ⋅ 5 = 5 ⋅ 10 = 50

Înmulțiți cu 6

Înmulțim primul factor cu 5, apoi adăugăm rezultatul.

• 1 ⋅ 6 = (1 ⋅ 5) + 1 = 5 + 1 = 6
• 2 ⋅ 6 = (2 ⋅ 5) + 2 = 10 + 2 = 12
• 3 ⋅ 6 = (3 ⋅ 5) + 3 = 15 + 3 = 18
• 4 ⋅ 6 = (4 ⋅ 5) + 4 = 20 + 4 = 24
• 5 ⋅ 6 = (5 ⋅ 5) + 5 = 25 + 5 = 30
• 6 ⋅ 6 = (6 ⋅ 5) + 6 = 30 + 6 = 36
• 7 ⋅ 6 = (7 ⋅ 5) + 7 = 35 + 7 = 42
• 8 ⋅ 6 = (8 ⋅ 5) + 8 = 40 + 8 = 48
• 9 ⋅ 6 = (9 ⋅ 5) + 9 = 45 + 9 = 54
• 10 ⋅ 6 = (10 ⋅ 5) + 10 = 50 + 10 = 60

Înmulțiți cu 7

Nu există un algoritm simplificat pentru înmulțirea cu 7, așa că folosim metode aplicabile altor factori.

• 1 ⋅ 7 = 7 ⋅ 1 = 7
• 2 ⋅ 7 = 7 ⋅ 2 = 7 + 7 = 14
• 3 ⋅ 7 = 7 ⋅ 3 = (7 ⋅ 2) + 7 = 21
• 4 ⋅ 7 = 7 ⋅ 4 = (7 ⋅ 2) + (7 ⋅ 2) = 28
• 5 ⋅ 7 = 7 ⋅ 5 = 7 + 7 + 7 + 7 + 7 = 35
• 6 ⋅ 7 = 7 ⋅ 6 = (7 ⋅ 5) + 7 = 42
• 7 ⋅ 7 = 7 + 7 + 7 + 7 + 7 + 7 + 7 = 49
• 8 ⋅ 7 = 7 ⋅ 8 = (7 ⋅ 4) + (7 ⋅ 4) = 56
• 9 ⋅ 7 = 7 ⋅ 9 = (7 ⋅ 10) – 7 = 63
• 10 ⋅ 7 = 70

Înmulțiți cu 8

Înmulțim primul factor cu 4, apoi adăugăm aceeași cantitate la rezultat.

• 1 ⋅ 8 = (1 ⋅ 4) + (1 ⋅ 4) = 8
• 2 ⋅ 8 = (2 ⋅ 4) + (2 ⋅ 4) = 16
• 3 ⋅ 8 = (3 ⋅ 4) + (3 ⋅ 4) = 24
• 4 ⋅ 8 = (4 ⋅ 4) + (4 ⋅ 4) = 32
• 5 ⋅ 8 = (5 ⋅ 4) + (5 ⋅ 4) = 40
• 6 ⋅ 8 = (6 ⋅ 4) + (6 ⋅ 4) = 48
• 7 ⋅ 8 = (7 ⋅ 4) + (7 ⋅ 4) = 56
• 8 ⋅ 8 = (8 ⋅ 4) + (8 ⋅ 4) = 64
• 9 ⋅ 8 = (9 ⋅ 4) + (9 ⋅ 4) = 72
• 10 ⋅ 8 = (10 ⋅ 4) + (10 ⋅ 4) = 80

Înmulțiți cu 9

Înmulțim primul factor cu 10, apoi îl scădem din rezultatul obținut.

• 1 ⋅ 9 = (1 ⋅ 10) – 1 = 10 – 1 = 9
• 2 ⋅ 9 = (2 ⋅ 10) – 2 = 20 – 2 = 18
• 3 ⋅ 9 = (3 ⋅ 10) – 3 = 30 – 3 = 27
• 4 ⋅ 9 = (4 ⋅ 10) – 4 = 40 – 4 = 36
• 5 ⋅ 9 = (5 ⋅ 10) – 5 = 50 – 5 = 45
• 6 ⋅ 9 = (6 ⋅ 10) – 6 = 60 – 6 = 54
• 7 ⋅ 9 = (7 ⋅ 10) – 7 = 70 – 7 = 63
• 8 ⋅ 9 = (8 ⋅ 10) – 8 = 80 – 8 = 72
• 9 ⋅ 9 = (9 ⋅ 10) – 9 = 90 – 9 = 81
• 10 ⋅ 9 = (10 ⋅ 10) – 10 = 100 – 10 = 90

Înmulțiți cu 10

Adăugați zero la sfârșitul celuilalt multiplicator.

• 1 ⋅ 10 = 10 ⋅ 1 = 10
• 2 ⋅ 10 = 10 ⋅ 2 = 20
• 3 ⋅ 10 = 10 ⋅ 3 = 30
• 4 ⋅ 10 = 10 ⋅ 4 = 40
• 5 ⋅ 10 = 10 ⋅ 5 = 50
• 6 ⋅ 10 = 10 ⋅ 6 = 60
• 7 ⋅ 10 = 10 ⋅ 7 = 70
• 8 ⋅ 10 = 10 ⋅ 8 = 80
• 9 ⋅ 10 = 10 ⋅ 9 = 90
• 10 ⋅ 10 = 10 ⋅ 10 = 100