Đáp án:
B1
a) ( -2 - 7) * ( -3 + 5)
-9 * 2 = -18
b) ( -7) ^2 * 2^3 - ( - 20)
= 49 * 8 + 20
= 49 * 28
= 1372
c) ( - 5 - 13) / ( - 3)
= -18 / ( -3 )
= 6
d) ( - 4 )^3 * 5^4 - 5^3
= ( - 64) * 625 - 125
= ( - 64) * 500
= - 320000
B2
a) B( 4) ∈ { 0 ; 4 ; 8 ; 12 }
b) U( - 8) ∈ { 1 ; 2 ; 4 ; 8 ; -1 ; -2 ; -4 ; -8 }
B4
a) - 81\123 = -27\41
b) 30 * 13\ -150 * 26 = -1 / 10
c) 6 * 7 - 6 * 4/ 6 + 3
= 6 - 2 / 6 + 3
= 4 / 9
B5
a) 1/5 vs 4/20
4/ 20 = 1/5
Vi 1=1 nen 1/5 = 1/5
⇒ 1/5 = 4/20
b) 12/39 vs 16/45
12/39 = 180/585
16/45 = 208/585
Vi 180<208 nen 180/585 < 208/585
⇒ 12/39 < 16/45
c) 64/9 vs 57/8
64/9 = 512/72
57/8 = 513/72
Vi 512 < 513 nen 512/72 < 513/72
⇒ 64/9 < 57/8
d) -2/15 vs -24/72
-24/72 = -1/ 3 = -5/15
Vi -2 > -5 nen -2/15 > -5/15
⇒ -2/15 > -24/72
B5
a) 125% = 125/100 = 5/4
55% = 55/100 = 11/20
-0,125 = _ 1/8
4 1/3 = 13/3
-7 1/5 = _ 36/5
b) 0,25 = 25/100 = 25%
12,9 = 12 9/10 = 129/10 = 1290/100 = 1290%
3/4 = 75/100 = 75%
2/5 = 40/100 = 40%
