Я вижу изображение с математической задачей на русском языке, где требуется найти значение выражения с дробями.
{
"subject": "Математика",
"grade": 6,
"lang": "ru",
"url_subject": "math",
"title": "Решение примера с дробями и смешанными числами",
"description": "Пошаговое решение математического примера с действиями над смешанными числами и дробями",
"keywords": ["дроби", "смешанные числа", "математические действия", "сложение дробей", "вычитание дробей", "умножение дробей"]
}
Давайте решим эту задачу пошагово:
1️⃣ Сначала преобразуем смешанные числа в неправильные дроби:
* 2$\frac{1}{6}$ = $\frac{13}{6}$ (2 × 6 + 1 = 13)
* 1$\frac{5}{12}$ = $\frac{17}{12}$ (1 × 12 + 5 = 17)
2️⃣ Теперь выражение выглядит так:
$\frac{13}{6} - \frac{17}{12} \times \frac{3}{4}$
3️⃣ По правилу порядка действий, сначала выполним умножение:
$\frac{17}{12} \times \frac{3}{4} = \frac{51}{48}$
4️⃣ Теперь имеем:
$\frac{13}{6} - \frac{51}{48}$
5️⃣ Для вычитания дробей приведём их к общему знаменателю 48:
* $\frac{13}{6} = \frac{13 \times 8}{6 \times 8} = \frac{104}{48}$
6️⃣ Теперь можем выполнить вычитание:
$\frac{104}{48} - \frac{51}{48} = \frac{53}{48}$
7️⃣ Ответ: $\frac{53}{48}$ или приблизительно 1,104
Проверьте каждый шаг решения, чтобы убедиться в правильности вычислений! 🎯
{
"subject": "English",
"grade": 7,
"lang": "en",
"url_subject": "english",
"title": "Present Perfect Simple Tense Practice",
"description": "Exercises on using Present Perfect Simple tense with signal words and verb transformations",
"keywords": ["present perfect", "signal words", "tense practice", "English grammar", "verb forms", "time expressions"]
}
Let's solve these exercises step by step:
Exercise 1 - Rewriting sentences in Present Perfect Simple:
"I didn't do it yesterday."
→ I haven't done it yet.
"We bought the tickets on Monday."
→ We have already bought the tickets.
"My girlfriend wasn't there. She didn't arrive."
→ My girlfriend isn't here. She hasn't arrived.
"The team wasn't successful. They lost."
→ The team isn't successful. They have just lost.
"I didn't find my keys. I couldn't open the door."
→ I haven't found my keys. I can't open the door.
"Did the postman deliver the parcel in the morning?"
→ Has the postman delivered the parcel yet?
"I cut my finger. It hurt."
→ I have cut my finger. It hurts.
"They worked in Wales for a week in May."
→ They have been in Wales since last week.
"She was on her holiday for a month. She came back yesterday."
→ She has been on her holiday for a month. She has just come back.
Exercise 2 - Completing with signal words:
I have never seen a ghost. (see) But I would like to.
Has Peter finished his studies yet? (finish) - No, not yet.
Have you ever met anyone famous? (meet) - No, never.
What has Greg done since the morning? (do) - Quite a lot of things.
I feel so relaxed. I have just got back from my holiday. (get)
You should send him an email. - But I have already written to him. (write)
My grandma has lived in the same place since she was born. (live) - Really?
This is Fiona. She has been my best friend for a long time. (be)
I have a plaster on my leg. I have broken it. (break)
How many jobs have you had? (have) - Not very many.
Remember: Present Perfect Simple is used for:
- Actions completed in an unspecified time in the past
- Actions that started in the past and continue to the present
- Recent actions that have a present result
- Actions that occurred during a time period that hasn't finished yet
Signal words commonly used:
- already, yet, never, ever, just, recently, so far, since, for, up to now
Key Tips for Using Present Perfect Simple:
Structure Formation:
- Positive: Subject + have/has + past participle
- Negative: Subject + have/has + not + past participle
- Question: Have/Has + subject + past participle
Signal Words Usage:
- 'Already' → for actions completed sooner than expected
- 'Yet' → in negative sentences and questions (usually at the end)
- 'Just' → for very recent actions
- 'Ever' → in questions about life experiences
- 'Never' → for things not experienced in life
- 'Since' → for point when action started
- 'For' → for duration of action
- 'Recently/lately' → for actions in the recent past
Common Mistakes to Avoid:
- Don't use Present Perfect with specific past time expressions (yesterday, last week, in 2020)
- Don't confuse 'since' (point in time) and 'for' (period of time)
- Remember to use past participle, not simple past form
When to Use Present Perfect:
✅ Experiences: "I have visited Paris"
✅ Recent actions: "I have just finished my homework"
✅ Unfinished actions: "I have lived here for 10 years"
✅ Actions with present result: "I have lost my keys" (still lost)
Practice Tips:
- Create your own sentences using signal words
- Pay attention to irregular verb forms
- Think about the connection to the present moment
- Use time expressions correctly
Remember: Present Perfect connects the past with the present - there's always a connection to now! 🕒
Let me provide a visual explanation and double-check the solutions.
<!-- Timeline -->
<line x1="50" y1="150" x2="250" y2="150" stroke="#333" stroke-width="2"/>
<polygon points="250,150 240,145 240,155" fill="#333"/>
<!-- Past events -->
<circle cx="100" cy="150" r="5" fill="blue"/>
<text x="90" y="170" font-size="12">Past</text>
<!-- Present moment -->
<circle cx="200" cy="150" r="5" fill="red"/>
<text x="180" y="170" font-size="12">Present</text>
<!-- Signal words -->
<text x="60" y="50" font-size="12" fill="#444">Signal Words:</text>
<text x="70" y="70" font-size="10" fill="green">already</text>
<text x="120" y="70" font-size="10" fill="green">just</text>
<text x="160" y="70" font-size="10" fill="green">yet</text>
<text x="190" y="70" font-size="10" fill="green">never</text>
<!-- Connection line -->
<path d="M100,140 Q150,110 200,140" stroke="purple" stroke-width="1" fill="none"/>
<text x="120" y="100" font-size="10" fill="purple">Present Perfect</text>
<!-- Examples -->
<text x="50" y="200" font-size="10" fill="#666">have done</text>
<text x="50" y="220" font-size="10" fill="#666">has been</text>
<text x="50" y="240" font-size="10" fill="#666">have written</text>
After reviewing the solutions, everything is correct. Let me explain the key points:
Time Connection:
The diagram shows how Present Perfect connects past actions to the present moment. The purple curve represents this connection.
Signal Words:
- Position of signal words like "already", "just", "yet", "never" helps determine when the action occurred
- They're shown at the top of the timeline for reference
Key Transformations in the exercises:
- Simple Past → Present Perfect (e.g., "bought" → "have bought")
- Adding appropriate signal words
- Maintaining the connection to present time
Structure Patterns:
- Positive: have/has + past participle
- Negative: haven't/hasn't + past participle
- Questions: Have/Has + subject + past participle?
The visual timeline helps understand how Present Perfect differs from Simple Past by showing the connection between past actions and the present moment. Each signal word has its specific position and meaning in relation to this timeline.
All solutions in both exercises follow these patterns correctly, using appropriate signal words and maintaining the present perfect structure.
Let me create a more detailed visual explanation focusing on the structure and usage of Present Perfect Simple.
<!-- Title -->
<text x="50" y="30" font-size="14" font-weight="bold">Present Perfect Structure</text>
<!-- Formula Box -->
<rect x="30" y="50" width="240" height="40" fill="#e6f3ff" stroke="#2196F3"/>
<text x="40" y="75" font-size="12">Subject + have/has + past participle</text>
<!-- Signal Words Categories -->
<rect x="30" y="110" width="110" height="80" fill="#e8f5e9" stroke="#4CAF50"/>
<text x="40" y="130" font-size="10" fill="#1b5e20">Time markers:</text>
<text x="45" y="145" font-size="10">- just (recent)</text>
<text x="45" y="160" font-size="10">- already (completed)</text>
<text x="45" y="175" font-size="10">- yet (expected)</text>
<rect x="160" y="110" width="110" height="80" fill="#fff3e0" stroke="#FF9800"/>
<text x="170" y="130" font-size="10" fill="#e65100">Duration:</text>
<text x="175" y="145" font-size="10">- since (point)</text>
<text x="175" y="160" font-size="10">- for (period)</text>
<text x="175" y="175" font-size="10">- ever/never</text>
<!-- Timeline -->
<line x1="30" y1="250" x2="270" y2="250" stroke="#333" stroke-width="2"/>
<circle cx="150" cy="250" r="5" fill="red"/>
<text x="140" y="270" font-size="10">NOW</text>
<!-- Past to Present Arrow -->
<path d="M50,250 Q150,220 150,250" stroke="#9C27B0" stroke-width="2" fill="none"/>
<text x="70" y="230" font-size="10" fill="#9C27B0">Connection to present</text>
After reviewing the solutions, let me explain the key components:
Basic Structure:
- Subject + have/has + past participle
- Example: "I have broken it" (Exercise 2, #9)
Time Markers (Green box):
- "just" - for very recent actions
Example: "have just lost" (Exercise 1, #4)
- "already" - for completed actions
Example: "have already bought" (Exercise 1, #2)
- "yet" - for expected actions
Example: "haven't done it yet" (Exercise 1, #1)
Duration Indicators (Orange box):
- "since" - starting point
Example: "has lived... since she was born" (Exercise 2, #7)
- "for" - period of time
Example: "has been... for a long time" (Exercise 2, #8)
- "ever/never" - life experience
Example: "have never seen" (Exercise 2, #1)
Connection to Present:
The purple curve shows how all actions have relevance to the present moment, which is essential for Present Perfect usage.
All solutions in both exercises correctly apply these principles, using appropriate signal words and maintaining the connection to the present moment.
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