Given a natural number n, the number of the numbers less than N and coprime with n is represented by a (n), and then a (2006)

Given a natural number n, the number of the numbers less than N and coprime with n is represented by a (n), and then a (2006)

This is Euler function
2006=2×17×59
So a (2006) = 2 ^ 0 × (2-1) × 17 ^ 0 × (17-1) × 59 ^ 0 × (59-1) = 928

Can we calculate the rolling friction directly with the formula

Yes, it's only introduced in college physics or basic physics. It's necessary to use the knowledge of the center of motion theorem and rigid body mechanics!

First find the rule, then fill in the number according to the rule
（1）0.1 0.3 0.5 0.7 0.9 ( )( ) （2）0.1 0.2 0.4 0.8 1.6 ( )( )
(3)0.01 0.04 0.09 0.16 0.25 ( )( )

1）0.1 0.3 0.5 0.7 0.9 ( 1.1 )( 1.3 )
（2）0.1 0.2 0.4 0.8 1.6 ( 3.2 )( 6.4 )
(3)0.01 0.04 0.09 0.16 0.25 ( 0.36 )(0.49 )

A and B are two natural numbers
One seventh less than a, b less than one sixth
 a＋b=22
Find the value of a and B

6b

Root 5 * 5 to the third power / root 5 to the fourth power =?
The second power of [1 / 2 power of 2 + 1 / 2 power of 3] =?
3-2 * radical 12 + 3 * radical 8 =?

All become the exponential power of 5, and then add and subtract the index: 5 ^ (7 / 12)
Expansion by complete square: 5 + 2 roots 6
Simplify the things in the root sign, and then calculate: 3-4 * root sign 2 + 6 * root sign 2

Simple calculation of 187 × 169 / 188

Original formula = 188x169 / 188-169 / 188
=169-169/188

Simplification: x ^ 2 + 2x / 1 + X ／ x ／ 2 / x + 1 =?

=x(x+2)/(x+1) ×1/x×(x+1)/2
=(x+2)/2

Find 20 binary linear equations (calculation problems),
Don't use thousands of them (e.g. 66x + 17Y = 3967), but use easy ones,
Don't have decimals

1,x-y=2xy=15 (x=5,y=3)2,x+y=6x-y=2 (4,2)3,x+y=11,xy=30 (x=5,y=6,x=6,y=5)4,x+y=13,xy=42 (x=6,7,y=7,6)5,x+y=11,x-y=1 (x=6,y=5)6,x+y=12,xy=35 (x=5,7,y=7,5)7,x+y=5,xy=6 (x=2,3,y=3,2)8,x-y=5,xy=36 (x=6,y=1...

Travel problems (1)
1. Party A and Party B go from East Street to West Street at the same time. Party A travels 120 meters per minute, and Party B travels 100 meters per minute. As a result, Party A arrives 5 minutes earlier than Party B. what is the distance between East Street and West Street?

120x5 = 600 (m) 120-100 = 20 (m) 600 △ 20 = 30 (min) 30x100 = 3000 (m)

44 of 45 × 37 =?

44/45×37
＝(1－1/45)×37
＝37－37/45
= 36 and 8 / 45