Definition

1. Verb phrase:
   • To calculate mentally / to do mental arithmetic: The act of performing mathematical calculations in one's head, without the use of writing, calculators, or other external aids.

Usage Examples

• (The teacher taught the students how to do mental arithmetic quickly.)
• (He can calculate the total sum mentally very fast.)
• (In the competition, contestants had to use mental calculation to answer.)

Advanced Usage

• "phép tính nhẩm": a mental calculation.
  • Những phép tính nhẩm phức tạp đòi hỏi sự tập trung cao. (Complex mental calculations require high concentration.)

Variants and Related Words

• Tính toán (v): to calculate, to compute (a general term that can involve any method).
  • Cô ấy tính toán chi phí cho chuyến đi. (She calculated the cost for the trip.)

Synonyms

• Mental calculation: the process of performing arithmetic in the mind.
• Mental arithmetic: the skill of calculating mathematical problems mentally.

Related Idioms

• Nhẩm tính: to estimate roughly in one's head.
  • Tôi nhẩm tính chi phí khoảng năm triệu đồng. (I roughly estimated the cost at about five million dong.)