1. Fill in the appropriate number in □.

( 1)58+47+42+53 =( + )+( + )

(2)38 1+236+464 = 38 1+( + )

(3)634- 123-477 =634-( )

(4) 125×7×8 = 125×( )

(5)235× 14+235×86 = 235×( + )

(6)2 100÷ 14 = 2 100÷ ÷

Second, the judgment question. (Mark "√" for the right and "×" for the wrong)

( 1)420÷2 1 = 420÷7×3 ( )

(2) 125×(8÷2)= 125×8×2 ( )

(3)483-(83+ 17)= 483-83+ 17 ( )

(4)56+a+44 = a+(56+44)()

(5) 10 1×43-43 = 100×43 ( )

Third, calculate the following questions, as simple as possible.

299+ 189+ 1 1 546- 127-373 76+ 14 1+59+ 124

45×9+45 720÷36 2400÷25÷4

87× 10 1 30×28-30× 13 808× 125

Fourth, the application problem.

1. Miss Li's home has 4 bookcases, and * * * has 9 floors with 25 books on each floor. How many books are there in Miss Li's house?

2. There are fruit trees 1268 in the orchard, including 475 pear trees, 325 jujube trees and the rest apple trees. How many apple trees are there?

There was a rose exhibition in the park. Red roses and yellow roses 15 rows, 24 pots of red roses and 26 pots of yellow roses. How many pots of red roses and yellow roses were put in?