Question

4. Calculează în două moduri: a) 7x9=6x9+9 = 54+9 -> 8x9= 4x7= 7x9= 9x9= 7 x 10 = 10 x 6 = 6 x 6 = 5x S= 6 x (10+ 0) = b) 7x9 = (7x4) + (7x5) = 28+35 → 4x 6 = 8x 5= 9x 9= 10 x 10 = 9x( 8+5) = 7x 7 = 9x10= 8x 8 = 1x 7=​

Answer 1

Răspuns:

Explicație pas cu pas:

Calculează în două moduri:

a) 7 x 9 = 6 x 9 + 9 = 54+9 = 63 → primul mod

   7 x (5+4) = (7 x 4) + (7 x 5) = 28 +35 = 63 → al doilea mod

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8 × 9 = 7 × 9 + 9 = 63 + 9 = 72

8 × 9 = 8 × (5+4) = 8×5 + 8×4 = 40 + 32 = 72 → al doilea mod

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4 ×7 = 3 × 7 + 7 = 21 + 7 = 28 → primul mod

4 × (5+2) = 4×5 + 4×2 = 20 + 8 = 28 → al doilea mod

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9 × 9 = 8 × 9 + 9 = 72 + 9 = 81 → primul mod

9 × (5+4) = 9×5 + 9×4 = 45 + 36 = 81 → al doilea mod

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7 × 10 = 6 × 10 + 10 = 60 + 10 = 70 → primul mod

7 × (5+5) = 7 × 5 + 7 × 5 = 35 + 35 = 70 → al doilea mod

sau: 7 × (10+0) = 7 × 10 + 7×0 = 70 + 0 = 70

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6 × 6 = 5 × 6 + 6 = 30 + 6 = 36 → primul mod

6 × (5+1) = 6×5 + 6×1 = 30 + 6 = 36 → al doilea mod

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4 × 6 = 3 × 6 + 6 = 18 + 6 = 24 → primul mod

4 × ( 5+1) = 4×5 + 4×1 = 20 + 4 = 24 → al doilea mod

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8 × 5 = 7 × 5 + 5 = 35 + 5 = 40 → primul mod

8 × ( 3+2) = 8×3 + 8×2 = 24 + 16 = 40 → al doilea mod

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10 × 10 = 9 × 10 + 10 = 90 + 10 = 100 → primul mod

10 × ( 5 + 5 ) = 10 ×5 + 10×5 = 50 + 50 = 100 → al doilea mod

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9 × ( 8+5) = 9 × 13 = 117 → primul mod

= 9×8 + 9 ×5 = 72 + 45 = 117 → al doilea mod

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9 × 10 = 8 × 10 + 10 = 80 + 10 = 90 → primul mod

= 9 × ( 5+5) = 9×5 + 9×5 = 45 + 45 = 90 → al doilea mod

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8 × 8 = 7 × 8 + 8 = 56 + 8 = 64 → primul mod

8 × (5+3) = 8×5 + 8×3 = 40 + 24 = 64 → al doilea mod

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1 × 7 = 0×7 + 7 = 0 + 7 = 7 → primul mod

1 × (5+2) = 1×5 + 1×2 = 5 + 2 = 7 → al doilea mod