9! - 8! - 7! . 8^2=362880-40320-5040.64=362880-40320-322560=322560-322560=0
9! - 8! - 7! . 8^2=362880-40320-5040.64=362880-40320-322560=322560-322560=0
1. Tính bằng cách hợp lý
1) 0,625 . 17/13 . 8/3 . -21/51 . (-6)
2) -7/9 . 24/19 + 7/9
3) -3/8 . 7/6 +3/8 . 9/6
Tính:9^9+8^8+7^7+6^6+5^5+4^4+3^3+2^2+1^1
Tính hợp lý:
a) ( -5/6 + 2/5) : 3/8 + ( 4/5 - 11/30) : 3/8
b) (-3/4 + 2/5) : 3/7 + ( 3/5 + -1/4) : 3/7
c)-13/18 . 5/8 + -5/18 . 2/9 + -13/18 . 3/8 + -5/18 . 7/9
d) -11/19 . 4/9 + -8/19 . 3/7 + -11/19 . 5/9 + -9/19 . 4/7
Tính:
1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9
Tính:
1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10
Tính
A=1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10
Tính : 9 ! - 8! - 7! . 8^2
tính(tính nhanh nếu có thể)
1/2+2/3.(2/3+3/4+4/5+5/6+6/7+7/8+8/9+9/10)
Tính 1) 4/5 +13/18 2) 3/7 -11/8 3) -7/10 - -4/5 4) 3/20 -1/25 5) 2/3 - 5/6 6) 1/4 + -3/8 - 19/10 7) -9/10 - -7/18 8) 3/10 - 11/18 9) 3/5 -5/6 + -7/12 10) -4/9 - (-5 )/6 - 3/8