Решебник по математике 4 класс Моро Часть 1, 2 Часть 1 Задание 12

\[\boxed{\text{12\ (12).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

Пояснение.

Решение.

\[1.\ 25 \cdot 3 = 75.\]

\[2.\ 500 - 75 = 425.\]

\[3.\ 470 - 425 = 45.\ \]

\[1.\ 160\ :4 = 40.\]

\[2.\ 300 + 40 = 340.\]

\[3.\ 340\ :2 = (200 + 140)\ :2 =\]

\[= 100 + 70 = 170.\ \]

\[1.\ 400 - 160 = 240.\]

\[2.\ 240 + 40 = 280.\]

\[3.\ 500 + 280 = 780.\ \]

\[1.\ 240 \cdot 3 = (200 + 40) \cdot 3 =\]

\[= 600 + 120 = 720.\]

\[2.\ 870 - 720 = 150.\]

\[3.\ 150\ :5 = 30.\ \]

\[1.\ 120 - 80 = 40.\]

\[2.\ 100\ :25 = 4.\]

\[3.\ 40\ :4 = 10.\ \]

\[1.\ 87 - 84 = 3.\]

\[2.\ 32 \cdot 3 = 96.\]

\[3.\ 100 - 96 = 4.\ \]

\[1.\ 140 \cdot 2 = 280.\]

\[2.\ 280 - 280 = 0.\]

\[3.\ 0 + 7 = 7.\ \]

\[1.\ 81\ :3 = (60 + 21)\ :3 =\]

\[= 20 + 7 = 27.\]

\[2.\ 9 \cdot 3 = 27.\]

\[3.\ 27\ :27 = 1.\]