General Mathematics WAEC

Fractions, Decimals And Approximations

Gbogbo ọrọ náà

Understanding fractions, decimals, and approximations is essential in the field of General Mathematics as they form the basis of numerical operations and real-world applications. In this course material, we will delve into the concepts of fractions, decimals, and approximations in great detail to equip students with the necessary knowledge and skills.

Fractions and decimals play a crucial role in representing numbers that are not whole. Fractions represent a part of a whole, such as 1/2 representing half of something, while decimals provide a way to express fractions in a decimal form. By understanding how fractions and decimals work, students will be able to tackle complex mathematical problems with ease.

Performing basic operations on fractions and decimals is another fundamental aspect of this course material. Students will learn how to add, subtract, multiply, and divide fractions and decimals efficiently. These operations are essential in various mathematical computations and real-life scenarios, making them indispensable skills for students to acquire.

Applying fractions and decimals in real-life situations is a key objective of this course material. Students will explore how fractions and decimals are used in everyday life, such as in measuring ingredients for a recipe, calculating discounts during sales, or determining proportions in a construction project. By relating mathematical concepts to real-world contexts, students will appreciate the practical significance of fractions and decimals.

Furthermore, appreciating the importance of approximations and significant figures is crucial for students to develop a keen sense of precision in their calculations. In the real world, numbers are often approximated to simplify calculations or make sense of data. Understanding when and how to use approximations and significant figures is essential in fields such as science, engineering, and economics.

In conclusion, this course material on fractions, decimals, and approximations will provide students with a solid foundation in numerical concepts and operations. By mastering these topics, students will not only enhance their mathematical skills but also gain a deeper insight into the practical applications of mathematics in various aspects of life.

Ebumnobi

  1. Appreciate the importance of approximations and significant figures
  2. Perform basic operations on fractions and decimals
  3. Apply fractions and decimals in real-life situations
  4. Course Objectives: Understand the concept of fractions and decimals

Akwụkwọ Ọmụmụ

Fractions represent parts of a whole. They are written in the form of a/b, where a is the numerator (the number of parts) and b is the denominator (the total number of equal parts the whole is divided into). For example, in the fraction 3/4, the numerator is 3, and the denominator is 4, which means we have 3 parts out of 4 equal parts of a whole.

Nnyocha Ọmụmụ

Ekele diri gi maka imecha ihe karịrị na Fractions, Decimals And Approximations. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

  1. What is the decimal equivalent of the fraction 3/4? A. 0.75 B. 0.25 C. 0.5 D. 0.3 Answer: A. 0.75
  2. Convert the decimal 0.625 to a fraction in simplest form. A. 5/8 B. 25/8 C. 25/4 D. 5/4 Answer: A. 5/8
  3. Perform the operation 1/3 + 2/5 A. 1 B. 1/2 C. 7/15 D. 5/3 Answer: C. 7/15
  4. What is the result of 0.6 * 0.25? A. 0.15 B. 0.025 C. 15 D. 0.015 Answer: A. 0.15
  5. Simplify the expression 0.4 + 0.16 - 0.25 A. 0.44 B. 0.55 C. 0.35 D. 0.45 Answer: A. 0.44
  6. Approximate the value of √7 to the nearest whole number. A. 2 B. 3 C. 4 D. 5 Answer: B. 3
  7. If a recipe calls for 2/3 cup of sugar and you need to make 4 times the recipe, how many cups of sugar will you need? A. 8/3 cups B. 1 1/3 cups C. 2 2/3 cups D. 4 2/3 cups Answer: D. 4 2/3 cups
  8. Which of the following numbers is closest to the value of π (pi)? A. 2 B. 3 C. 3.14 D. 3.5 Answer: C. 3.14
  9. If you round 346.879 to the nearest whole number, what do you get? A. 346 B. 347 C. 350 D. 340 Answer: B. 347

Ajụjụ Nnyocha

Nna, you dey wonder how past questions for this topic be? Here be some questions about Fractions, Decimals And Approximations from previous years.

Ajụjụ 1 Ripọtì

Evaluate, correct to four significant figures, (573.06 x 184.25).

Akọwa Nkọwa

573.06 x 184.25 = 105,586.305

1,05600.00 to four significant figure

What are the Rules for significant figures?

Significant Figures

  • All non-zero numbers ARE significant.
  • Zeros between two non-zero digits ARE significant. 
  • Leading zeros are NOT significant.
  • Trailing zeros to the right of the decimal ARE significant.
  • Trailing zeros in a whole number with the decimal shown ARE significant.

Ajụjụ 1 Ripọtì

A banker spent \(\frac{1}{5}\) of his salary on shirts,  \(\frac{1}{3}\) of the remainder on transport, and kept the rest for contingencies. What fraction was left

Akọwa Nkọwa

The key to solving this problem is to follow each step of the spending process, keeping track of what fraction of the salary is left after each transaction. We can use algebra to represent and simplify each step:


  • Step 1: Spending on shirts
    The banker spends \( \frac{1}{5} \) of his salary on shirts.
    Let the whole salary be \( S \). The amount spent on shirts is \( \frac{1}{5}S \).
    That means the remainder is: \[ S - \frac{1}{5}S = \frac{4}{5}S \]

  • Step 2: Spending on transport
    Next, the banker spends \( \frac{1}{3} \) of the remainder (which is \( \frac{4}{5}S \)) on transport:
    \[ \text{Amount spent on transport} = \frac{1}{3} \times \frac{4}{5}S = \frac{4}{15}S \]
    The new remainder (what he has left after transport) is: \[ \frac{4}{5}S - \frac{4}{15}S \] To subtract these, write both with a common denominator: \[ \frac{4}{5}S = \frac{12}{15}S \] \[ \frac{12}{15}S - \frac{4}{15}S = \frac{8}{15}S \]

  • Step 3: Fraction left for contingencies
    At the end, the banker is left with \( \frac{8}{15} \) of his original salary.
    So the fraction left is \( \frac{8}{15} \).

Summary: The banker spends some money at each step, and each time the new amount spent is a fraction of what's left, not a fraction of the original salary. After both expenses, the fraction remaining is \( \frac{8}{15} \) of the starting salary.


Ajụjụ 1 Ripọtì

A man travels at a rate of 25m/sec. If he travels for 10½hrs, how many kilometres has he covered?