Математика 3 класс Т.Е.Демидова, С.А.Козлова, А.П.Тонких Номер 9

В = 310 \overset{1}{:} 5 \overset{3}{+} 123 \overset{2}{*} 3 = 431

1) 310 : 5 = (300 + 10) : 5 = 60 + 2 = 62
2) 123 * 3 = (100 + 20 + 3) * 3 = 300 + 60 + 9 = 369
3) 62 + 369 = (60 + 2) + (300 + 60 + 9) = 300 + (60 + 60) + (2 + 9) = 300 + 120 + 11 = 420 + 11 = 431

М = (245 \overset{1}{:} 245 \overset{2}{+} 699) \overset{3}{:} 5 = 140

1) 245 : 245 = 1
2) 1 + 699 = 700
3) 700 : 5 = (500 + 200) : 5 = 100 + 40 = 140

Н = 90 \overset{1}{:} 15 \overset{2}{*} 78 \overset{3}{-} 278 = 190

1) 90 : 15 = 6
2) 6 * 78 = 6 * (70 + 8) = 420 + 48 = 468
3) 468 − 278 = 468 − 268 − 10 = 200 − 10 = 190

У = 572 \overset{3}{-} (95 \overset{1}{*} 4 \overset{2}{-} 105) = 297

1) 95 * 4 = (90 + 5) * 4 = 360 + 20 = 380
2) 380 − 105 = 380 − 100 − 5 = 280 − 5 = 275
3) 572 − 275 = 572 − 272 − 3 = 300 − 3 = 297

И = (678 \overset{1}{-} 678) \overset{2}{*} 125 \overset{3}{:} 5 = 0

1) 678 − 678 = 0
2) 0 * 125 = 0
3) 0 : 5 = 0

А = 600 \overset{4}{-} (125 \overset{1}{*} 4 \overset{3}{-} 25 \overset{2}{*} 4) = 200

1) 125 * 4 = (100 + 20 + 5) * 4 = 400 + 80 + 20 = 400 + 100 = 500
2) 25 * 4 = (20 + 5) * 4 = 80 + 20 = 100
3) 500 − 100 = 400
4) 600 − 400 = 200

Ы = 48 \overset{1}{:} 12 \overset{2}{*} 235 \overset{3}{-} 298 = 642

1) 48 : 12 = 4
2) 4 * 235 = 4 * (200 + 30 + 5) = 800 + 120 + 20 = 800 + 140 = 940
3) 940 − 298 = 940 − (240 + 50 + 8) = 940 − 240 − 50 − 8 = 700 − 50 − 8 = 650 − 8 = 642

Ц = 125 \overset{1}{:} 5 \overset{3}{+} 23 \overset{2}{*} 9 = 232

1) 125 : 5 = (100 + 25) : 5 = 20 + 5 = 25
2) 23 * 9 = (20 + 3) * 9 = 180 + 27 = 180 + 20 + 7 = 207
3) 25 + 207 = 25 + 200 + 7 = 200 + 32 = 232

Ответ: ВЫ УМНИЦЫ

ГДЗ учебник по математике 3 класс Т.Е.Демидова, С.А.Козлова, А.П.Тонких

Номер №9

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