Do these in your head-i 12 -7-8 -7ii 29 -2-21 -2iii 2-7-17-5-7-17iv 11-9-5-7-9-5v 1-5 -9-0-5 -9vi 3-4 -7-0-6 -7vii 4 -0-19-6 -0-19

(i) (12 × (−7)) + (8 × (−7)) = (12 + 8) × (−7) = 20 × (−7) = −140 nbsp; (ii) (29 × (−2)) + (21 × (−2)) = (29 + 21) × (−2) = 50 × (−2) = −100 nbsp; ...

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Byju's Answer

Standard VIII

Mathematics

Distributive Property of Rational Numbers

Do these in y...

Question

Do these in your head:

(i) (12 × (−7)) + (8 × (−7))

(ii) (29 × (−2)) + (21 × (−2))

(iii)

(iv)

(v) (1.5 × (−9)) + (0.5 × (−9))

(vi) (3.4 × (−7)) + (0.6 × (−7))

(vii) (4 × (−0.19)) + (6 × (−0.19))

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Solution

(i)

(12 × (−7)) + (8 × (−7)) = (12 + 8) × (−7)

= 20 × (−7)

= −140

(ii)

(29 × (−2)) + (21 × (−2)) = (29 + 21) × (−2)

= 50 × (−2)

= −100

(iii)

+ =

_{= 1 × (−17)}

= −17

(iv)

+ =

= 2 × (−5)

= −10

(v)

(1.5 × (−9)) + (0.5 × (−9)) = (1.5 + 0.5) × (−9)

= 2 × (−9)

= −18

(vi)

(3.4 × (−7)) × (0.6 × (−7)) = (3.4 + 0.6) × (−7)

= 4 × (−7)

= −28

(vii)

(4 × (−0.19)) + (6 × (−0.19)) = (4 + 6) × (−0.19)

= 10 × (−0.19)

= −1.9

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Similar questions

Q. Multiply.
(i)

(- 5) \times (- 7)

(ii)

(- 9) \times (6)

(iii)

(9) \times (- 4)

(iv)

(8) \times (- 7)

(v)

(- 124) \times (- 1)

(vi)

(- 12) \times (- 7)

(vii)

(- 63) \times (- 7)

(viii)

(- 7) \times (15)

Re-arrange suitably and find the sum in each of the following :

(i) $\frac{11}{12} + \frac{- 17}{3} + \frac{11}{2} + \frac{- 25}{2}$

(ii) $\frac{- 6}{7} + \frac{- 5}{6} + \frac{- 4}{9} + \frac{- 15}{7}$

(iii) $\frac{3}{5} + \frac{7}{3} + \frac{9}{5} + \frac{- 13}{15} + \frac{- 7}{3}$

(iv) $\frac{4}{13} + \frac{- 5}{8} + \frac{- 8}{13} + \frac{9}{13}$

(v) $\frac{2}{3} + \frac{- 4}{5} + \frac{1}{3} + \frac{2}{5}$

(vi) $\frac{1}{8} + \frac{5}{12} + \frac{2}{7} + \frac{7}{12} + \frac{9}{7} + \frac{- 5}{16}$

Q. Evaluate:

(i) \frac{3}{7} + \frac{- 4}{9} - \frac{- 11}{7} - \frac{7}{9}

(i i) \frac{2}{3} + \frac{- 4}{5} - \frac{1}{3} - \frac{2}{5}

(i i i) \frac{4}{7} - \frac{- 8}{9} - \frac{- 13}{7} + \frac{17}{9}

Evaluate :

$(i) \frac{3}{7} + \frac{- 4}{9} + \frac{- 11}{7} + \frac{7}{9} (i i) \frac{2}{3} + \frac{- 4}{5} + \frac{1}{3} + \frac{2}{5} (i i i) \frac{4}{7} + 0 + \frac{- 8}{9} + \frac{- 13}{7} + \frac{17}{9} (i v) \frac{3}{8} + \frac{- 5}{12} + \frac{3}{7} + \frac{3}{12} + \frac{- 5}{8} + \frac{- 2}{7}$

Fill in the blanks.

(i) $(\frac{- 3}{17}) + (\frac{- 12}{5}) = (\frac{- 12}{5}) + (. . . . .)$

(ii) $- 9 + \frac{- 21}{8} = (. . . . . .) + (- 9)$

(iii) $(\frac{- 8}{13} + \frac{3}{7}) + (\frac{- 13}{4}) = (. . . . . .) + [\frac{3}{7} + (\frac{- 13}{4})]$

(iv) $- 12 + (\frac{7}{12} + \frac{- 9}{11}) = (- 12 + \frac{7}{12}) + (. . . . .)$

(v) $\frac{19}{- 5} + (\frac{- 3}{11} + \frac{- 7}{8}) = {\frac{19}{- 5} + (. . . . .)} + \frac{- 7}{8}$

(vi) $\frac{- 16}{7} + . . . . . = . . . . . . + \frac{- 16}{7} = \frac{- 16}{7}$

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Do these in your head: (i) (12 × (−7)) + (8 × (−7)) (ii) (29 × (−2)) + (21 × (−2)) (iii) (iv) (v) (1.5 × (−9)) + (0.5 × (−9)) (vi) (3.4 × (−7)) + (0.6 × (−7)) (vii) (4 × (−0.19)) + (6 × (−0.19))

Do these in your head:

(i) (12 × (−7)) + (8 × (−7))

(ii) (29 × (−2)) + (21 × (−2))

(iii)

(iv)

(v) (1.5 × (−9)) + (0.5 × (−9))

(vi) (3.4 × (−7)) + (0.6 × (−7))

(vii) (4 × (−0.19)) + (6 × (−0.19))