Page 225 - คณิตศาสตร์ ม.ต้น

218

แบบฝกหัดที่ 5

จงหาผลลัพธ 
1). [(-3)  (-5)]  (-2) 6). (-5)  [6 + (-6)]

วิธีทํา [(-3)  (-5)]  (-2) = 15  (-2) วิธีทํา (-5)  [6 + (-6)] = (-5) 0

= (-30) = 0

2). (-3)  [(-5)  (-2)] 7). [(-7)  (-5)] + [(-7)  2]

วิธีทํา (-3)  [(-5)  (-2)] = (-3)  10 วิธีทํา [(-7)  (-5)] + [(-7)  2] = 35 + (-14)

= -30 = 21
3). [4  (-3)]  (-1) 8). (-7)  [(-5) + 2]

วิธีทํา [4  (-3)]  (-1) = (-12)  (-1) วิธีทํา (-7)  [(-5) + 2] = (-7)  (-3)

= 12 = 21

4). 4  [(-3)  (-1)] 9). [5  (-7)] + [5  3]
วิธีทํา 4  [(-3)  (-1) ] = 4  3 วิธีทํา [5  (-7)] + [5  3] = (-35) + 15

= 12 = (-20)

5). [(-5)  (-6)] + [(-5) (-6)] 10). 5  [(-7) + 3]
วิธีทํา [(-5)  (-6)] + [(-5)  (-6)] = 30+30 วิธีทํา 5  [(-7) + 3] = 5  (-4)

= 60 = (-20)