4. จงหาผลลัพธ์
1) 20(8 + 12)
วิธีทำ
20(8 + 12)
= 20(20)
= 400
ตอบ 400
2) (20 x 8) + (20 x 12)
วิธีทำ
(20 x 8) + (20 x 12)
= 160 + 240
= 400
ตอบ 400
3) 14[10 + (-9)]
วิธีทำ
14[10 + (-9)]
= 14(10 – 9)
= 14(1)
= 14
= 14
ตอบ 14
4) (14 x 10) + [14 x (-9)]
วิธีทำ
(14 x 10) + [14 x (-9)]
= 140 + [-(14 x 9)]
= 140 + (-126)
= 140 – 126
= 14
= 140 – 126
= 14
ตอบ 14
5) 28 x [-2 + (-3)]
วิธีทำ
28 x [-2 + (-3)]
= 28 x [-(2 + 3)]
= 28 x (-5)
= -(28 x 5)
= -140
= -(28 x 5)
= -140
ตอบ -140
6) [28(-2)] + [28(-3)]
วิธีทำ
[28(-2)] + [28(-3)]
= [-(28(2))] + [-(28(3))]
= (-56) + (-84)
= -(56 + 84)
= -140
= -(56 + 84)
= -140
ตอบ -140
7) -6 x (-20 + 5)
วิธีทำ
-6 x (-20 + 5)
= (-6) x [-(20 – 5)]
= (-6) x (-15)
= 6 x 15
= 90
= 6 x 15
= 90
ตอบ 90
8) [(-6) · (-20)] + [(-6) · 5]
วิธีทำ
[(-6) · (-20)] + [(-6) · 5]
= (6 · 20) + [-(6 · 5)]
= 120 + (-30)
= 120 – 30
= 90
= 120 – 30
= 90
ตอบ 90
9) (-10) x [(-5) + (-15)]
วิธีทำ
(-10) x [(-5) + (-15)]
= (-10) x [-(5 + 15)]
= (-10) x (-20)
= 10 x 20
= 200
= 10 x 20
= 200
ตอบ 200
10) [-10(-5)] + [-10(-15)]
วิธีทำ
[-10(-5)] + [-10(-15)]
= [10(5)] + [10(15)]
= 50 + 150
= 200
= 200
ตอบ 200
11) 2 x [27 + (-9)]
วิธีทำ
2 x [27 + (-9)]
= 2 x (27 – 9)
= 2 x 18
= 36
= 36
ตอบ 36
12) [2(27)] + [2(-9)]
วิธีทำ
[2(27)] + [2(-9)]
= 54 + [-(2(9))]
= 54 + (-18)
= 54 – 18
= 36
= 54 – 18
= 36
ตอบ 36