31/5div8/5*21/10 eching

$$3 \frac { 1 } { 5 } \div \frac { 8 } { 5 } \times 2 \frac { 1 } { 10 }$$

Baholash

$$\frac{21}{5}=4,2$$

Yechim qadamlari

\frac{3\times 5+1}{5} ni \frac{8}{5} ga bo'lish \frac{3\times 5+1}{5} ga k'paytirish \frac{8}{5} ga qaytarish.

$$\frac{\left(3\times 5+1\right)\times 5}{5\times 8}\times \frac{2\times 10+1}{10}$$

Surat va maxrajdagi ikkala 5 ni qisqartiring.

$$\frac{1+3\times 5}{8}\times \frac{2\times 10+1}{10}$$

15 hosil qilish uchun 3 va 5 ni ko'paytirish.

$$\frac{1+15}{8}\times \frac{2\times 10+1}{10}$$

16 olish uchun 1 va 15'ni qo'shing.

$$\frac{16}{8}\times \frac{2\times 10+1}{10}$$

2 ni olish uchun 16 ni 8 ga bo‘ling.

$$2\times \frac{2\times 10+1}{10}$$

20 hosil qilish uchun 2 va 10 ni ko'paytirish.

$$2\times \frac{20+1}{10}$$

21 olish uchun 20 va 1'ni qo'shing.

$$2\times \frac{21}{10}$$

2\times \frac{21}{10} ni yagona kasrga aylantiring.

$$\frac{2\times 21}{10}$$

42 hosil qilish uchun 2 va 21 ni ko'paytirish.

$$\frac{42}{10}$$

\frac{42}{10} ulushini 2 ni chiqarib, bekor qilish hisobiga eng past shartlarga kamaytiring.

$$\frac{21}{5}$$

Omil

$$\frac{3 \cdot 7}{5} = 4\frac{1}{5} = 4,2$$