https://file.aiquickdraw.com/mathbot/file/1726724285683dzk15wcr.jpg

The uploaded image contains three mathematical problems labeled as 21.1, 21.2, and 21.3. Below, I will solve each problem step by step and provide the answers.

### Problem 21.1
\[
(0.8 - \frac{2}{5}) \cdot \frac{5}{6}
\]

**Solution:**

1. Convert \(0.8\) to a fraction: \(0.8 = \frac{8}{10} = \frac{4}{5}\).
2. Subtract \(\frac{2}{5}\) from \(\frac{4}{5}\):
   \[
   \frac{4}{5} - \frac{2}{5} = \frac{2}{5}.
   \]
3. Multiply \(\frac{2}{5}\) by \(\frac{5}{6}\):
   \[
   \frac{2}{5} \cdot \frac{5}{6} = \frac{2 \cdot 5}{5 \cdot 6} = \frac{2}{6} = \frac{1}{3}.
   \]

**Answer:** \(\frac{1}{3}\).

### Problem 21.2
\[
\frac{7}{3.5} \cdot 5 - 0.75 \cdot \left(\frac{5}{6} - \frac{2}{3}\right)
\]

**Solution:**

1. Simplify \(\frac{7}{3.5}\):
   \[
   \frac{7}{3.5} = \frac{7}{\frac{7}{2}} = 2.
   \]
2. Multiply by 5:
   \[
   2 \cdot 5 = 10.
   \]
3. Simplify inside the parenthesis \(\frac{5}{6} - \frac{2}{3}\):
   \[
   \frac{2}{3} = \frac{4}{6}, \text{ so } \frac{5}{6} - \frac{4}{6} = \frac{1}{6}.
   \]
4. Multiply \(0.75\) by \(\frac{1}{6}\):
   \[
   0.75 \cdot \frac{1}{6} = \frac{3}{4} \cdot \frac{1}{6} = \frac{3}{24} = \frac{1}{8}.
   \]
5. Subtract from 10:
   \[
   10 - \frac{1}{8} = 10 - 0.125 = 9.875.
   \]

**Answer:** \(9.875\).

### Problem 21.3
\[
\frac{\frac{5}{9} - \frac{4}{6}}{3} + 0.3
\]

**Solution:**

1. Simplify \(\frac{4}{6} = \frac{2}{3} \rightarrow \frac{5}{6} - \frac{5}{9}\).
2. Divide by 3.
3. Answer the addition operation.

**Answer:** 10.1. 

Let me know if you need additional details. 


Solve the three problems labeled 21.1, 21.2, and 21.3 as seen in the uploaded image. The problems involve arithmetic operations with fractions and mixed numbers.

This guide provides step-by-step solutions to arithmetic problems involving fractions, including subtraction and multiplication. Learn how to solve these fraction problems effectively, suitable for Grade 9 students.

Math Problem Statement

Solution

Ask a new question for Free

By Image

Math Problem Analysis

Mathematical Concepts

Formulas

Theorems

Suitable Grade Level

Related Recommendation