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(- 7) - (- 8) + (- 9) - 14 should be calculated simply
(-7)-(-8)+(-9)-14
=-7+8-9-14
=8-(7+9+14)
=8-30
=-(30-8)
=-22
1 () 2 () 3 () 4 () 5 () 6 () 7 () 8 (), add a sign in the bracket to make the result of the circular formula equal to 100
1×2+3×4+5×6+7×8=100
Friendly tips: multiply first, then add
1(*)2(+)3(*)4(+)5(*)6(+)7(*)8 =100
1x2+3x4+5x6+7x8=100
How to cycle?
In Japan, the three most commonly used modes of transportation to school are: bus, train and bicycle
In Japan, the school's three most popular modes of transportation are: buses, trains and bicycles
Simple calculation 7 / 8 - 7 / 8 × 2 / 9 = please
7/8 -7/8×2/9=7/8*1-7/8×2/9=7/8*(1-2/9)=7/8*7/9=49/72
Add appropriate operation symbols to 9, 13, 7 and 100 to form a two-step formula with the number of 100
9+13X7=100
What's the English for buses, subways and airplanes?
Bus: Bus: plane: subway has a variety of views, different countries have different views, words are not the same
One by one plus two by one-third plus three by one-quarter
I'm relatively young. I hope you can give me a more detailed answer,
1*1/2+2*1/3+3*1/4…… 2013*1/2014
=1-1/2+1-1/3+1-1/4…… 1-1/2014
=2013-(1/2+1/3+1/4…… +1/2014)
This kind of sequence in brackets is called harmonic sequence, and its summation formula has not been found yet,
When n is quite large, the following approximate formula can be used:
1+1/2+1/3+1/4+...1/n = ln(n) + γ
Euler approximately calculated the value of γ, which is about 0.577218. This number is later called Euler constant
That is to say, ln (2014) + γ - 1 in brackets
So = 2014-ln (2014) - 0.577 = 2014-7.608-0.577 = 2005.815
(1 * 2) 1 + (2 * 3) 1 + (3 * 4) 1 + +(2013 * 2014) 1 / 2
= 1-2 / 1 + 2 / 1-3 / 1 + 3 / 1-4 / 1 + 1 / 2013-1 / 2014
= 1-1 / 2014
= 2013 / 2014
1.5 1.5 1.5 1.5 1.5 1.5 1.5 is equal to 8, fill in the operation symbol and bracket to make the formula hold,
(1.5 + 1.5) ^ (1.5 + 1.5) / 1.5 is the second power of 3 = 9
For example, take the subway train to the people's Square and the bus to the railway station,
This is the bus/subway heading to xxx This is the bus/subway towards the direction of xxx This is the subway heading to Renmin Square/PlazaThis the bus towards train station.
Math problem: 1 times 1 / 2 plus 2 times 1 / 3 plus 3 times 1 / 4, all the way to 56 times 1 / 57, what's the result?
It's 1 / (1 × 2) + 1 / (2 × 3) + 1 / (3 × 4) + +1 / (56 × 57)?
The original formula = (1-1 / 2) + (1 / 2-1 / 3) + (1 / 3-1 / 4) + +(1/56-1/57)=1-1/57=56/57
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