120 ° - 18 ° 25'36 "= attach method if possible

120 ° - 18 ° 25'36 "= attach method if possible

120°-18°25′36〃
=(119°+59′+60〃)-(18°+25′+36〃)
=(119°-18°)+(59′-25′)+(60〃-36〃)
=111°34′24〃

How to calculate 18 + 120% x = 30

18+120%x=30
120%x=30-18
1.2x=12
x=12÷1.2
x=10

21 ~ 29 these nine numbers are placed in the nine palaces of three horizontally and three vertically. How can they add up to 75

If you have a good guess, this figure should be a figure in which the word "Tian" coincides with the word "Mi", and Chinese mathematics is called "nine palace grid". The specific solution is as follows: first, let the middle number be a, and the sum of three numbers on each line be B, then consider that the sum of four numbers on the line of "Mi" should be 4B, According to the meaning of the question, we can get such a formula: (21 + 22 + 23 + 24 + - - + 29 + 3a) = 4B. Because a can only be a number between 21 and 29, 4b can be an integer between 288 and 312, and can be divided by 4. In this way, there are seven formulas: 4B = 288, 292, 296, 300, 304, 308 and 312. After simplifying the formula, we get a = (4b-225) △ 3 So we have to satisfy that 4B minus 225 can be divided by 3, so 4B can only choose 300, then the middle number a is equal to 25, the number in each line and B = 75, the middle number is determined, the number in each line is determined, and the answer is 28 21 26 23 25 27 24 29 22 --------?. ● ya è. Thank you o (∩)_ ∩) O... Hope to bring a good comment ~ ★ x 5!

1 × 2 / 1 + 2 × 3 / 1 + ······ + 99 × 100 / 1, the answer is coming

1 × 2 / 1 + 2 × 3 / 1 + ······ + 99 × 100 / 1
=1-1/2+1/2-1/3+1/3-1/4+…… +1/99-1/100
=1-1/100
=99/100