Найдите сумму: 1. -12+(-18) 2. -1,7+(-23) 3. -7-25 4. -3,4+(-1,7) 5. -8-1,3 6. -\frac{2}{3}+(-\frac{1}{4}) 7. -100+(-50) 8. -6,25+(-2,75) 9. -\frac{5}{6}+(-\frac{2}{9}) 10. -42-38 11. -15+(-35) 12. -\frac{3}{8}+(-\frac{5}{12})

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ФИО:Телефон:Емаил:Полное описание сути нарушения прав (почему распространение данной информации запрещено Правообладателем):

Accepted Answer

$$ -12 + (-18) = - (12 + 18) = -30 $$
$$ -1.7 + (-23) = -(1.7 + 23) = -24.7 $$
$$ -7 - 25 = -7 + (-25) = -(7 + 25) = -32 $$
$$ -3.4 + (-1.7) = -(3.4 + 1.7) = -5.1 $$
$$ -8 - 1.3 = -8 + (-1.3) = -(8 + 1.3) = -9.3 $$
$$ -\frac{2}{3} + (-\frac{1}{4}) = -(\frac{2}{3} + \frac{1}{4}) = -(\frac{2 \cdot 4}{3 \cdot 4} + \frac{1 \cdot 3}{4 \cdot 3}) = -(\frac{8}{12} + \frac{3}{12}) = -\frac{11}{12} $$
$$ -100 + (-50) = -(100 + 50) = -150 $$
$$ -6.25 + (-2.75) = -(6.25 + 2.75) = -9 $$
$$ -\frac{5}{6} + (-\frac{2}{9}) = -(\frac{5}{6} + \frac{2}{9}) = -(\frac{5 \cdot 3}{6 \cdot 3} + \frac{2 \cdot 2}{9 \cdot 2}) = -(\frac{15}{18} + \frac{4}{18}) = -\frac{19}{18} = -1\frac{1}{18} $$
$$ -42 - 38 = -42 + (-38) = -(42 + 38) = -80 $$
$$ -15 + (-35) = -(15 + 35) = -50 $$
$$ -\frac{3}{8} + (-\frac{5}{12}) = -(\frac{3}{8} + \frac{5}{12}) = -(\frac{3 \cdot 3}{8 \cdot 3} + \frac{5 \cdot 2}{12 \cdot 2}) = -(\frac{9}{24} + \frac{10}{24}) = -\frac{19}{24} $$