Đáp án:

Giải thích các bước giải:

 1.Lenght of the side of a square is:

100:10=10 (m)

10 m= 1000 cm

Perimeter of a square is:

1000x4=4000 cm

The number of pieces we need to enclose a square is:

4000: 160= 25( pieces)

xIn lỗi bài 2 mình hok thấy

Answer:

1)

Exchange `160cm = 1.6m`

The area of the square is `100m^2`

`=>` The side of the square is 10m because

`10 × 10 = 100`

The number of pieces of wire `160cm` long to take to wrap a square with an area of

`100 m^2` is : `10 : 1.6 = 6.25` ( paragraph )

Change `6.25 =` `6 1/4` paragraph

Answer: `6 1/4` paragraph

2)

The units digit has `3` choices (since it's an even number, the units digit can only be `0`, `2` or `4` )

Tens digit has `4` choices

Hundreds digit has `3` choices

The thousands digit has `1` choice

So it is possible to generate all even `4` digit numbers that are different:

`3 × 4 × 3 × 1 = 36` ( number )

Answer: `36` numbers