The simple calculation of 83 + 78 + 80 + 77 + 84 + 79 is

The simple calculation of 83 + 78 + 80 + 77 + 84 + 79 is

(80+3)+(80-2)+80+(80-3)+(80+4)+(80-1)=80*6+(3-2-3+4-1)=480+1

How much is 82 + 84 + 79 + 78 + 80 + 83?

These five numbers are all close to 80, so they are calculated by 80 first, and then the difference is calculated
The method is as follows
（80+2）+（80+4）+（80-1）+（80）+（80+3）=80*5+2+4-1+0+3=408

83 + 82 + 79 + 77 + 85 + 79 (simple calculation)

83＋82＋79＋77＋85＋79
＝80＋3＋80＋2＋80－1＋80－3＋80＋5＋80－1
＝80×6＋(3＋2－1－3＋5－1)
＝480＋5
＝485

1.6 × 3 / 5 is equal to?

X + 1 / 2-x + 1 / 4 equals 1 / 6-x-1 / 4

1/(x+2)-1/(x+4)=1/(x-6)-1/(x-4)
2/(x+2)(x+4)=2/(x-6)(x-4)
So x + 2) (x + 4) (X-6) (x-4)
x²+6x+8=x²-10x+24
x=1
By testing, x = 1 is the solution of the equation

1. To solve the equation, 3 out of 8 and 5 out of 6 are equal to 1 and 2 out of 1

3 out of 8 plus 5 out of 6 = 3
3 out of 8 = 3-3 out of 6
3 out of 8 = 15 out of 6

1 of 3 × 4 + 1 of 4 × 5 + 1 of 5 × 6 + 1 of 6 × 7 + 1 of 7 × 8 + 1 of 8 × 9 is equal to?

They don't look to the end

What's the equivalent of 7 / 9 + 99 + 7 / 8 + 999 + 7 / 8 + 3 / 8?

9 and 8 of 7 + 99 and 8 of 7 + 999 and 8 of 7 + 8 of 3
=10-1/8+100-1/8+1000-1/8+3/8
=1110-3*1/8+3/8
=1110

999 7 / 8 + 99 3 / 4 + 10 1 / 4 + 7 / 8
Urgent!

The original question should be 999 7 / 8 + 99 3 / 4 + 10 1 / 4 + 1 / 8
999 7 / 8 + 99 3 / 4 + 10 1 / 4 + 1 / 8
=999 7 / 8 + 1 / 8 + 99 3 / 4 + 10 1 / 4
=1000+110
=1110

Write an algorithm for 1 + 1 / 2 + 1 / 3 up to 1 / 100

This can't be calculated. This is the sum of 1 / N. there is no formula
The sequence composed of the reciprocal of natural numbers is called harmonic sequence. People have studied it for hundreds of years. But so far, there is no summation formula for it, only its approximate formula (when n is very large)
1 + 1 / 2 + 1 / 3 +. + 1 / N ≈ lnn + C (C = 0.57722. An irrational number, called Euler initial, is specially used for Harmonic Series)
People tend to think that it does not have a simple summation formula
However, it is not because it is divergent that there is no summation formula. On the contrary, for example, the arithmetic sequence is divergent, and the arithmetic sequence whose absolute value of common ratio is greater than 1 is also divergent. They all have summation formulas