1m=100cm

cạnh của hình vuông là : 100: 4= 25 cm

S hình vuông là: 25* 25=625 cm = 6,25 m

Rewrite the sentences below, using ENOUGH instead of TOO

1. He is too old to wear this coloured shirt.

=> He isn't young enough to wear this coloured shirt

2. She is too weak to carry this bag.

=> She isn't healthy enough to carry this bag

3. This pen is too expensive for me to buy.

=> This pen isn't cheap enough for me to buy

4. Bill is too foolish to understand what I say.

=> Bill isn't intelligent enough to understand what i say

5. This bag is too heavy for her to carry.

=> This bag isn't light enough for her to carry

6. The test was too difficult for them to do.

=> the test isn't easy enough for them to do

7. That sentences was too long for me to memorize.

=> That sentences wasn't short enough for me to memorize

8. The land is too poor to grow crops.

=> The land isn't rich enough to grow crops

9. The room is too noisy for us to study.

=> The room isn't quiet enough for us to study

10. This book is too dull to read.

=> This book isn't interesting enough to read

11. We were too late to get good grades.

=> We weren't early enough to get good grades

Từ trang 1 đến trang 9 có :

(9 - 1) + 1 = 9 ( số )

Từ trang 10 đến trang 99 có :

(99 - 10) + 1 = 90 ( số )

Từ trang 100 đến trang 257 có :

(257 - 100) + 1 = 158 ( số ) 

Vậy để đánh số một quyển sách dày 257 trang cần :

9 x 1 + 90 x 2 + 158 x 3 = 663 ( chữ số )

k cho mk nha bn

Cần tất cả số mét dây kẽm gai để rao là :

    42 x 4 = 168 ( m )

          ĐS : 168 m

ab + ba = 66

A * 10 + b * 10 + a = 66

a * 11 + b * 11 = 66

=> a = b = 3

Thử lại : ab + a = 66

=> 33 + 33 = 66