3.1 - 4.9 = - ( 4.9 - 3.1) = -1.8
-.2.4 + 8.7 = 8.7 - 2.4 = 6.3
-1/5 + 8/15 = 8/15 - 1/5 = 8/15 - 3/15 = 5/15 = 1/3
-3 1/3 - 1 1/6 = - (3 1/3 + 1 1/6 ) = - (3 2/6 + 1 1/6) = - 4 3/6 = - 4 1/2 = -4.5
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2.03 - x = 2.3
-x = 2.3 - 2.03
-x = 0.27
x = -0.27
<span>2 1/7 + y= - 2 1/7
</span>y = - 2 1/7 - 2 1/7
y = - (2 1/7 + 2 1/7)
y = - 4 2/7
1)14+7=21 (д) девочек
2)14+21=35 (д)
Ответ:35 детей построились
Ну помойму 180-90=90,90:2=45(манд.)
1)4,6*3,5=16,1
2)16,1-20,8= -4,7(отрицательное число)