الخطط

حاسبة التقريب: المنازل العشرية والأرقام المعنوية

تقرّب هذه الحاسبة العدد إلى عدد المنازل العشرية أو الأرقام المعنوية الذي تختاره، أو إلى أقرب عشرة أو مئة أو ألف وهكذا. وتبيّن أي رقم يحسم الأمر، ولماذا يُقرَّب العدد للأعلى أو يبقى كما هو.

النتيجة

أدخل القيم واضغط احسب لرؤية النتيجة.

الصيغة

next digit≥5⇒round up;<5⇒keep\text{next digit} \geq 5 \Rightarrow \text{round up}; \quad < 5 \Rightarrow \text{keep}

Look at the digit just after the last one you keep. Halves round away from zero, so 2.5 → 3 and −2.5 → −3.

كيفية استخدام هذه الحاسبة

  1. Enter the number. Decimals, negative numbers and fractions such as 2/3 all work.
  2. Choose decimal places, significant figures or a place value, and how many.
  3. Press Calculate to see the rounded number and the digit that decided it.

أمثلة محلولة

Round 3.14159 to 2 decimal places

Keep two digits after the point: 3.14. The next digit is 1.

1 is less than 5, so the 4 stays the same: 3.14.

Round 0.0045678 to 3 significant figures

Leading zeros are not significant, so the first significant figure is 4. Keep 4, 5 and 6.

The next digit is 7, which is 5 or more, so round up: 0.00457.

Round 1,234,567 to the nearest thousand

The thousands digit is 4 and the next digit (hundreds) is 5.

5 rounds up, so the answer is 1,235,000.

Round 2.5 to the nearest whole number

The digit after the point is 5, so round up to 3.

Round 9.996 to 3 significant figures

Keep 9, 9 and 9; the next digit is 6, so round up. 9.99 becomes 10.0.

The zero after the point is kept: it is the third significant figure.

أخطاء شائعة

  • Rounding in several stages (2.445 → 2.45 → 2.5). Always round the original number once.
  • Counting leading zeros as significant figures: 0.0045 has 2 significant figures.
  • Dropping zeros that matter: 2.50 to 3 significant figures keeps the final 0.

الأسئلة الشائعة

How do you round to 2 decimal places?

Look at the third digit after the point. If it is 5 or more, add 1 to the second digit; otherwise leave it. 3.14159 → 3.14 and 2.678 → 2.68.

What are significant figures?

The digits that carry meaning, starting from the first non-zero digit. 0.04560 has 4 significant figures: 4, 5, 6 and the final 0.

Does 5 round up or down?

At school, 5 rounds up (away from zero), so 2.5 → 3 and 7.45 to one decimal place → 7.5. Some software uses “round half to even” instead.