Current location - Training Enrollment Network - Mathematics courses - The answer (50~5 1) of Math 4.2 in Shanghai textbook is very accurate, and I will be very grateful =3=
The answer (50~5 1) of Math 4.2 in Shanghai textbook is very accurate, and I will be very grateful =3=
One.

2.

Two. ××××

Three. 50.24 square centimeters? 25.12cm

12.56cm2? 15.7 km2

four

Four.

1. 125.6 divided by 3. 14 divided by 2=20cm? 2.4÷2=2m 2+ 1=3m? 3. 143×3-2×2= 15.7m2? 15.7× 800 =12.5t.

3. 14×20×20= 1256cm2

5 1 page

I s = 3. 14x 1x 1 = 3. 14c m2 c = 2x 1x 3. 14 = 6.28cm? 3. 14x 1x=3. 14? 3. 14x2x2= 12.56cm2? 12.56-3. 14 = 9.42 cm2.

Two. 1.3x2x3. 14= 18.84cm? 100 x 18.84 = 1884cm 2。 ? 20÷2= 10cm? 10x 10=3 14cm2

3. 18.84÷3. 14=6m? 3. 14x6x 6÷2 = 56.52 square meters

4. 120x2=240m? 3.14x20 = 62.8m 240+62.8 = 302.8m.

I don't know if it's right. Y (_) y is expected.