Fractions, decimals and percentages

Học bằng cách chơi

Trả lời những câu hỏi này để kiếm năng lượng, rồi câu cá và khám phá. Không cần tài khoản.

Dành cho nhà giáo dục: slide bài học, ghi chú ôn tập sẵn dùng cho Fractions, decimals and percentages (Mathematics, Number) — dùng trong bài giảng của bạn, hoặc chạy chủ đề như một hoạt động lớp học tương tác để người học chơi như một trò chơi trực tiếp.

Ghi chú bài học Slide Câu hỏi luyện tập

Ghi chú bài học

Fractions, decimals and percentages are linked

They are three ways of writing the same part of a whole: \frac{1}{4} = 0.25 = 25\%.
Fraction to decimal: divide the numerator by the denominator. \frac{3}{8} = 3 \div 8 = 0.375.
Decimal to percentage: multiply by 100. Percentage to decimal: divide by 100.
Learn the common equivalents: \frac{1}{2} = 0.5 = 50\%, \frac{1}{5} = 0.2 = 20\%, \frac{3}{4} = 0.75 = 75\%, \frac{1}{3} = 0.\dot{3}.

One quarter in three forms

Operations with fractions

Add/subtract: use a common denominator. \frac{2}{3} + \frac{1}{4} = \frac{8}{12} + \frac{3}{12} = \frac{11}{12}.
Multiply: multiply numerators and denominators. \frac{2}{3} \times \frac{3}{5} = \frac{6}{15} = \frac{2}{5}.
Divide: multiply by the reciprocal. \frac{3}{4} \div \frac{2}{5} = \frac{3}{4} \times \frac{5}{2} = \frac{15}{8}.
For mixed numbers, convert to improper fractions first.
A reciprocal exists only for a nonzero number. Division by zero is undefined.

Percentages of amounts

Find 10% by dividing by 10 and build up: 15% of 80 = 8 + 4 = 12.
Using a multiplier: 15% of 80 = 0.15 \times 80 = 12.
To write one amount as a percentage of another, divide and multiply by 100: 18 out of 40 is \frac{18}{40} \times 100 = 45\%.

Recurring decimals

A recurring decimal repeats forever: 0.\dot{3} = \frac{1}{3}, 0.\dot{1}\dot{8} = 0.181818....
To convert to a fraction, let x equal the decimal, multiply to line up the repeat, then subtract. For x = 0.\dot{4}: 10x - x = 4, so x = \frac{4}{9}.

Ordering and comparing

Convert everything to the same form (usually decimals) before comparing.
Compare \frac{3}{5}, 0.58 and 62%: they are 0.6, 0.58 and 0.62, so the order is 0.58, \frac{3}{5}, 62%.

Slide

Step through every slide for this topic — plus flashcards and revision notes — with a free account.

ĐĂNG KÝ — MIỄN PHÍ ĐĂNG NHẬP

Câu hỏi luyện tập

Xem trước miễn phí — 8 trên 32 câu hỏi. Đăng ký để xem tất cả.

1.What is 50% as a fraction in its simplest form?
Easy
- A\frac{1}{5}
- B\frac{1}{2}
- C\frac{5}{10}
- D\frac{1}{4}
2.Write 0.6 as a percentage.
Easy
- A6%
- B0.6%
- C60%
- D600%
3.Write 35% as a decimal.
Easy
- A3.5
- B0.35
- C0.035
- D35
4.What is \frac{3}{4} as a percentage?
Easy
- A34%
- B75%
- C43%
- D60%
5.Work out \frac{1}{3} + \frac{1}{6}.
Easy
- A\frac{2}{9}
- B\frac{1}{2}
- C\frac{2}{6}
- D\frac{1}{9}
6.Work out \frac{5}{6} - \frac{1}{4}.
Easy
- A\frac{4}{2}
- B\frac{7}{12}
- C\frac{4}{10}
- D\frac{1}{3}
7.Work out \frac{2}{3} \times \frac{3}{5}.
Easy
- A\frac{5}{8}
- B\frac{2}{5}
- C\frac{6}{8}
- D\frac{10}{9}
8.Work out 2\frac{1}{2} \times 3.
Easy
- A6\frac{1}{2}
- B7\frac{1}{2}
- C6 1/3
- D5\frac{1}{2}

Thêm câu hỏi

9.What is 15% of 80?
Easy
- A8
- B12
- C15
- D120
10.What is 35% of 200?
Easy
- A35
- B70
- C7
- D700
11.Write 18 out of 40 as a percentage.
Easy
- A18%
- B40%
- C45%
- D22%
12.Work out \frac{3}{5} \div \frac{9}{10}.
Medium
- A\frac{27}{50}
- B\frac{2}{3}
- C\frac{3}{2}
- D\frac{5}{9}
13.Work out 1\frac{2}{3} + 2\frac{3}{4}.
Medium
- A3\frac{5}{7}
- B4\frac{5}{12}
- C3\frac{5}{12}
- D4\frac{1}{7}
14.Which is the largest: \frac{3}{5}, 0.58 or 62%?
Medium
- A\frac{3}{5}
- B0.58
- C62%
- DThey are equal
15.Which list is in ascending order?
Medium
- A\frac{1}{2}, 0.4, 45%
- B0.4, 45%, \frac{1}{2}
- C45%, 0.4, \frac{1}{2}
- D\frac{1}{2}, 45%, 0.4
16.Which fraction equals 0.\dot{4}?
Medium
- A\frac{4}{10}
- B\frac{4}{9}
- C\frac{4}{99}
- D\frac{2}{5}
17.Write 0.\dot{1}\dot{8} as a fraction in its simplest form.
Medium
- A\frac{18}{99}
- B\frac{2}{11}
- C\frac{1}{8}
- D\frac{9}{50}
18.A coat costing £80 is reduced by 15%. What is the sale price?
Medium
- A£12
- B£68
- C£65
- D£92
19.In a class of 30, 12 are boys. What percentage are girls?
Medium
- A40%
- B60%
- C18%
- D12%
20.\frac{3}{5} of a number is 18. What is the number?
Medium
- A10.8
- B30
- C24
- D90
21.What is the reciprocal of \frac{2}{7}?
Easy
- A\frac{2}{7}
- B\frac{7}{2}
- C-\frac{2}{7}
- D\frac{5}{7}
22.Which method gives 8% of 250?
Medium
- A8 \times 250
- B0.08 \times 250
- C0.8 \times 250
- D250 \div 8
23.Which is the equivalent fraction to \frac{2}{3}?
Easy
- A\frac{4}{9}
- B\frac{4}{6}
- C\frac{3}{2}
- D\frac{2}{6}
24.What is \frac{7}{20} as a percentage?
Easy
- A7%
- B20%
- C35%
- D3.5%
25.\frac{1}{4} is the same as 25%.
Easy
True or false?
26.To divide by a nonzero fraction, multiply by its reciprocal.
Easy
True or false?
27.\frac{2}{5} + \frac{3}{5} = \frac{5}{10}.
Easy
True or false?
28.0.07 is the same as 70%.
Easy
True or false?
29.0.\dot{3} is exactly equal to \frac{1}{3}.
Medium
True or false?
30.Which of these are equal to \frac{3}{4}?
Medium
- A0.75
- B75%
- C\frac{6}{12}
- D\frac{9}{12}
- E0.34
31.Which are recurring decimals?
Medium
- A\frac{1}{3}
- B\frac{1}{4}
- C\frac{2}{9}
- D\frac{1}{5}
- E\frac{5}{11}
32.Explain how to convert 0.\dot{6} to a fraction.
Medium

Unlock all 32 questions & more

Tạo tài khoản miễn phí để xem mọi câu hỏi, slide, thẻ ghi nhớ và ghi chú ôn tập cho chủ đề này.

ĐĂNG KÝ — MIỄN PHÍ ĐĂNG NHẬP

Đề thi cũ

Luyện đề thi cũ cho chủ đề này sắp ra mắt.

Sắp ra mắt