Greatest common factor and least common multiple 13 and 12 13 and 91 34 and 51

Greatest common factor and least common multiple 13 and 12 13 and 91 34 and 51

The greatest common factors of 13 and 12 are 1, the least common multiple 13 × 12 = 156, 13 and 91, the greatest common factor 13, the least common multiple 91.34 and 51, the greatest common factor 17, and the least common multiple 2 × 3 × 17 = 102

The greatest common divisor of 34 and 51 is______ ; & nbsp; & nbsp; the least common multiple of 12, 16, 24 is______ ．

① 34 = 2 × 17, 51 = 3 × 17, so the greatest common divisor of 34 and 51 is: 17; ② 12 = 2 × 2 × 3, 16 = 2 × 2 × 2 × 2, 24 = 2 × 2 × 2 × 3, so the least common multiple of 12, 16 and 24 is: 2 × 2 × 2 × 2 × 3 = 48, so the answer is: 17, 48

How about 11 + 12. + 29 and 1 + 2. + 50
To simplify the calculation, we need to know the answer quickly!

(11+29)+(12+28)+(13+27)+(14+26)+(15+25)+(16+24)+(17+23)+(18+22)+(19+21)+20=40+40+40+40+40+40+40+40+40+20=380(1+49)+(2+48)+(3+47)+(4+46)+(5+45)+(6+44)+(7+43)+(8+42)+().+50=50*25+50=1300

1 / 12 * 13 + 1 / 13 * 14 +. + 1 / 19 * 20? Why?

Using: 1 / N * (n + 1) = 1 / n-1 / (n + 1)
So: 1 / (12 × 13) + 1 / (13 × 14) + +1/（19×20）
=1/12-1/13+1/13-1/14+.+1/19-1/20
=1/12-1/20=1/30

1 / (12 * 13) + 1 / 13 * 14) - 1 / (19 * 20) value=

Original formula = (1 / 12-1 / 13) + (1 / 13-1 / 14) - (1 / 19-1 / 20)
=1/12-1/14-1/19+1/20
=1/84-1/380
=37/3990

-1 / 10 * 11 + 1 / 11 * 12 + 1 / 12 * 13 + 1 / 13 * 14 + ·· 1 / 19 * 20

If the title is right
-1/10*11+1/11*12+1/12*13+1/13*14+···1/19*20
= -1/10+1/11+1/11-1/12++···+1/19-1/20
=-1/10+1/11+1/11-1/20
=2/11-3/20
If it is
1/10*11+1/11*12+1/12*13+1/13*14+···1/19*20
=1 / 10-1 / 20 = 1 / 20 middle cancellation

1 + 2 = 3 4 + 5 + 6 = 7 + 8 9 + 10 + 11 + 12 = 13 + 14 + 15

The first number of the nth formula is the root n & # 178;, and there are n + 1 numbers, increasing at one time
So the 100th formula 100 & # 178;, 100 & # 178; + 1, ·· 100 & # 178; + 100,
The sum of all numbers is 101 * 100 & # 178; + 5050 = 1015050
If you are not satisfied, please continue to ask questions. If you are satisfied, you will be given points~

11+12+13+… +49 simple

11+12+13+…… +49
=(11+49)+(12+48)+(13+47)+……
=60+60+60+……
=60×[(49-10)÷2]
=60×39÷2
=1170

11+12+13+… +49 by a simple method

Summation formula of arithmetic sequence:
Sum of items = (first item + last item) * number of items / 2
=(11+49)*(49-11+1)/2
=60*39/2
=60/2*39
=30*39
=1170

Find the value of [1 / 10-1 / 11] + [1 / 11-1 / 12] +. [1 / 49-1 / 50]
[] = absolute value sign / = fractional line

[1 / 10-1 / 11] + [1 / 11-1 / 12] +. [1 / 49-1 / 50]
=1/10-1/11+1/11-1/12…… +1/49-1/50
=1/10-1/50
=2/25
All right, I'll get it for you