تمرين2
أحسب ما يلي
10 + 8 + 4 + 9 + 2 = 33
1 – 8 – 1 = 1 +(-8) +(-1)
= 1 + (-1) + (-8)
= 0 + (-8) = -8
5 + 2 + 10 + 10 + 4 = 31
5 + 6 x 3 + 5 = 5 + 18 +5 =28
6 + 3 –8 x –9 = 9 - (-8x9)
= 9-(-72)
= 9+72
= 81
5 ÷ 5 + 5 + 2 = (5 ÷ 5) +7
= 1 + 7 = 8
9 + 9 + 16 ÷ 4 = 18 + 4
= 22
7 x 7 – 9 ÷ 1 + 9 = 49 - 9 + 9
= 49
1 + 1(7 + 2) = 1 + (7 + 2)
= 1 + 9
= 10
9 + 2(10 – 5) = 9 + 2x5
= 9 + 10 = 19
9 + 9 ÷ (1 + 8) = 9 + 9 ÷9
= 9 + 1 = 10
5 + 2 ÷ (9 – 8) = 5 + 2 ÷ 1
= 5 + 2 = 7
2 + 8[1 + 7(9 + 1) + 4] = 2 + 8[1 + 7 x10 + 4]
= 2 + 8[1 + 70 + 4]
= 2 + 8x75
=2 + 600
= 602
9 + 3[9 + 4(2 – 4) + 7] = 9 + 3[9 + 4(-2) + 7]
=9 + 3[9 + (-8) + 7]
= 9 + 3 x8
= 9 + 24
= 33
1 + 10[1 + 6 ÷ (5 + 1) + 5] = 1 + 10[1 + 6 ÷6 + 5]
=1 + 10[1 + 1 + 5]
=1 + 10X7
=1 + 70
= 71
18 + 20[8 – 13 ÷ (12 + 1) + 2] =18 + 20[8 – 13 ÷ 13 + 2]
=18 + 20[8 – 1 + 2]
=18 + 20X9
=18 +180
=198
5 + 6{7 + 1[7 + 8(2 + 2) + 1] + 8} =5 + 6{7 + 1[7 + 8X4 + 1] + 8}
=5 + 6{7 + 1[7 + 32 + 1] + 8}
=5 + 6{7 + 40 + 8}
=5 + 6X55
=5 + 330
=335
2 – 1{8 + 3[8 + 2(10 + 9) + 1] + 1} =2 – 1{8 + 3[8 + 2X19+ 1] + 1}
=2 – 1{8 + 3[8 + 38 + 1] + 1}
=2 – 1{8 + 3X47 + 1}
=2 – 1{8 + 141 + 1}
=2 – 150
= – 148
1 – 9{2 – 8[2 + 8 ÷ (1 + 1) + 4] + 2}=
=1 – 9{2 – 8[2 + 8 ÷ 2 + 4] + 2}
=1 – 9{2 – 8[2 + 4 + 4] + 2}
=1 – 9{2 – 8X10 + 2}
=1 – 9{2 – 80 + 2}
=1 – 9X(-76)
=1 –(-684)
=1+684
=685