a) Tính nhanh
(1+3+5+7+.......+2003+2005).(125 125.127-127 127.125)
b) ho làm tính hãy so sánh:
A =1991.1999 và B=1995.1995
Tính nhanh:
a. ( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125)
b. 19 , 8 : 0 , 2 x 44 , 44 x 2 x 13 , 2 : 0 , 25 3 , 3 x 88 , 88 : 0 , 5 x 6 , 6 : 0 , 125 x 5
a. Vì 125 125x127 – 127 127x125 = 1001x125x127 – 1001x127x125 = 0
nên : (1+3+5+...+2005)(125 125x127 – 127 127x125) = 0
b.
19 , 8 : 0 , 2 x 44 , 44 x 2 x 13 , 2 : 0 , 25 3 , 3 x 88 , 88 : 0 , 5 x 6 , 6 : 0 , 125 x 5 = 19 , 8 x 5 x 88 , 88 x 13 , 2 x 4 3 , 3 x 88 , 88 x 2 x 6 , 6 x 8 x 5 = 19 , 8 x 5 x 88 , 88 x 13 , 2 x 4 3 , 3 x 88 , 88 x 13 , 2 x 4 x 2 x 5 = 19 , 8 3 , 3 x 2 = 3
Tính nhanh
( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125)
( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125)
= ( 1+3+5+7+…+2003+2005) x (125 x 1001 x 127 – 127 x 1001x 125)
= ( 1+3+5+7+…+2003+2005) x 0 = 0
Tính nhanh:
( 1 + 3 + 5 + 7 + … + 2003 + 2005 ) x ( 125 125 x 127 )
Vì 125 125x127 – 127 127x125 = 1001x125x127 – 1001x127x125 = 0
nên : (1+3+5+...+2005)(125 125x127 – 127 127x125) = 0
1a, tính nhanh:( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125) b,Một số tăng thêm 25% thì phải giảm đi bao nhiêu phần trăm số mới đẻ được số ban đầu?
ko cần tính hãy so sánh
A=1991.1999 B=1995.1995
A = 1991.1999 = 1991 . (1995 + 4) = 1991.1995 + 1991.4
B = 1995.1995 = (1991 + 4) . 1995 = 1995.1991 + 1995.4
Vì 1991.4 < 1995.4 nên A < B
Vậy A < B
tính nhanh
< 1+3+5+7...+2003+2005 > x <125 125x125-127 127x125>
các bạn ơi,sửa cho mình la 125 125x127 nhé
tính nhanh :
( 1 + 3 + 5 + 7 + ... + 2003 + 2005 ) . ( 125 125 . 127 - 127 127 . 125)
Mọi người ơi , giúp mình với . Mai mình phải nộp bài rồi
\(\left(1+3+5+7+...+2003+2005\right)\cdot\left(125125\cdot127-127127\cdot125\right)\\ =\left(1+3+5+7+...+2003+2005\right)\cdot\left(125\cdot1001\cdot127-127\cdot1001\cdot125\right)\\ =\left(1+3+5+7+...+2003+2005\right)\cdot0=0\)
tính nhanh
( 1+3+5+7+...+2003+2005 ) x ( 125125 x 127 - 127127 x 125 )
giúp mik vs
( 1 + 3 + 5 + 7 +... + 2003 + 2005 ) x ( 125125 x 127 - 127127 x 125 )
= ( 1 + 3 + 5 + 7 + ... + 2003 + 2005 ) x ( 125 x 1001 x 127 - 127 x 1001 x 125 )
= ( 1 + 3 + 5 + 7 + ... + 2003 + 2005 ) x 0
= 0
~ Thiên Mã ~
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tính bằng cách thuận tiện: dấu ''/ '' là tách nhau thành phân số :)
a.(1 +3+5+7+...+2003+2005)x(125 125x127- 127 127 x125)
b.1 000 x0,04-100:2,5+10x0,4
c.A=1/35+1/63+1/99+...+1/399+1/483
125 125 x 127 - 127 127 x 125
⇒ Dấu cách là dấu gì hả bạn?
a, (1 + 3 + 5 + 7+ ... + 2003 + 2005) x (125125 x 127 - 127127 x125)
= (1 + 3 + 5 +...+2003 + 2005) x (125 x 1001 x 127 - 127x1001 x 125)
= (1 + 3 + 5 +...+ 2003 + 2005) x 0
= 0
b; 1000 x 0,04 - 100 : 2,5 + 10 x 0,4
= 100 x 0,4 - 100 x 0,4 + 10 x 0,4
= 0 + 4
= 4