Numbers questions | form one Basic Mathematics

Find the product of the LCM and GCF of 20,60 and 120.

Answer / Solution

LCM is the product of all factors, while GCF is the product of all the common factors of numbers.
Given numbers 20 , 60, 120

Hence LCM of 20, 60 and 120 is found by multiplying all factors i.e 2 × 2 × 2 × 3 × 5 = 120
GCF of 20, 60 and 120 is found by multiplying the common factors i.e 2 × 2 × 5 = 20
Therefore the product of LCM and GCF of 20, 60 and 120 is:
120 × 20 = 2400.

Express in the form of ^a/_b where a and b are integers such that b≠0.NB: leave your answer in improper fraction.

Answer / Solution

UNSOLVED

Evaluate 20 - (7 ÷4) × 2 + 9 -3.

Answer / Solution

This is a BODMAS problem

steps

1. B(find brackets)
2. O(open brackets)
3. D(Division)
4. M(Multiplication)
5. A(Addition)
6. S(Subtraction)    

Hence

20 - 7 ÷ 4 × 2 + 9 -3 =  20 -1.75 × 2 + 9 -3.

20 - 3.5 + 9 -3 = 20 + 5.5 - 3.

25.5 - 3 = 22.5.

∴ 20 - 7 ÷ 4 × 2 + 9 -3 = 22.5

Find two consecutive odd numbers whose product is 35.

Answer / Solution

Let the two consecutive  odd numbers be x and y.

but we already know that

X x Y =35 and subtracting two consecutive odd numbers should give 2 that is Y-X=2 then

The two numbers are 5 and 7

Solve

• 342 - 18 × 9 =
• 70000-100000

Answer / Solution

• Following the principle of BODMAS

342-(18x9)

342-162=180

• 70000-100000= -30000