2007 minus 2008 =?

2007 minus 2008 =?

2007 minus 1 multiplied by (- 1) ^ 2007 = - 1
Multiplying 2008 negative ones equals (- 1) ^ 2008 = 1
So - 1-1 = - 2

2009 × (1 / 2009-1 / 2009) times (1 / 2008-1 / 2008) times (1 / 2007-1 / 2007) times Multiply by (1-2 / 2)

2009 × (1 / 2009-1 / 2009) times (1 / 2008-1 / 2008) times (1 / 2007-1 / 2007) times Multiply by (1-2 / 2)
=2009*2008/2009*2007/2008*2006/2007*.*3/4*2/3*1/2
=1

2、 Calculation: ① 0.625 × 50 + 0.625 × 3.46 + 5.346 × 3.75; ② 1 + 1 / 2 + 1 / 6 + 1 / 12 + 1 / 20 + 1 / 30 + 1 / 30 + 1 / 42 + 1 / 56; ③ (7 / 9)

My God! Use a calculator! There's no need to waste time on calculation

Among the numbers of 0.61, 0.603, 0.625, 0.663, 5 / 3 and 5 / 8, the largest is (), the smallest is (); and () and () are equal

Among the numbers of 0.61, 0.603, 0.625, 0.663, 5 / 3 and 5 / 8, the largest is (5 / 3), the smallest is (0.603); (5 / 8) and (0.625) are equal

0.625 * 0.5 + 5 / 8 + 1 / 2 * 62.5% =?

0.625 * 0.5 + 5 / 8 + 1 / 2 * 62.5%
=0.625×（0.5+1+1/2）
=0.625×2
=1.25

How easy is it to be 5 / 0.625-5 / 8

Five eighths = 0.625
5÷0.625=8
Five eighths △ 5 = 1 / 8
8-1/8=63/8

Simple calculation of 21.6 times 9.9

21.6*9.9
=21.6*（10-0.1）
=216-2.16
=213.84

In a mathematics competition, there are 10 questions in total, 8 points for each right question and 5 points for each wrong question. Xiaoyu finally gets 41 points, and he does it right______ Question

Suppose you do it all right and wrong: (10 × 8-41) / (48 + 5), = 39 / 13, = 3 (TAO); do it right: 10-3 = 7 (TAO); answer: he does it right. So the answer is: 7

A total of 10 questions, Xiaoqiang finally got 70 points, how many questions did he do right?

Suppose you do it all right
10 × 10 = 100 (min)
100-70 = 30 points, 30 points more than the actual score
Wrong: 30 ÷ (10 + 5) = 2 (question)
Right: 10-2 = 8 (question)
The typical chicken and rabbit cage problem, the hypothetical solution strategy

Use a simple method to calculate the following questions. 3 / 8 × 81 - 3 / 8 × 99 / 98 / 97 / 3 × 25

Three eighths × 81 - three eighths: three eighths × (81-1) = 30; 99 × 98 97: 99 × (1-98) = 99-98 99 = 97 and 98 97; nine thirteenth × 25: (10-13 1) × 25 = 13 10 * 25-13 1 * 25 = 13 250-13 25 = 13 225 = 17 and 13 4. I hope I can help you