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JSS2: MATHEMATICS - 1ST TERM

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  1. Properties of Whole Numbers I | Week 1
    4 Topics
    |
    1 Quiz
  2. Properties of Whole Numbers II | Week 2
    4 Topics
    |
    1 Quiz
  3. Properties of Whole Numbers III | Week 3
    5 Topics
    |
    1 Quiz
  4. Indices | Week 4
    2 Topics
    |
    1 Quiz
  5. Laws of Indices | Week 5
    5 Topics
    |
    1 Quiz
  6. Whole Numbers & Decimal Numbers | Week 6
    4 Topics
    |
    1 Quiz
  7. Standard Form | Week 7
    3 Topics
    |
    1 Quiz
  8. Significant Figures (S.F) | Week 8
    4 Topics
    |
    1 Quiz
  9. Fractions, Ratios, Proportions & Percentages I | Week 9
    6 Topics
    |
    1 Quiz
  10. Fractions, Ratios, Proportions & Percentages II | Week 10
    4 Topics
    |
    1 Quiz
  11. Fractions, Ratios, Proportions & Percentages III | Week 11
    3 Topics
    |
    1 Quiz
  12. Approximation & Estimation | Week 12
    1 Topic
    |
    1 Quiz
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Topic Content:

  • Increasing or Decreasing a Quantity in a Given Ratio
  • End of Lesson Evaluation Questions

1. To increase a given quantity by a given ratio, use the ratio as a multiplying factor such that the numerator is greater than the denominator.

2. To decrease a given quantity by a given ratio, use the ratio as a multiplying factor such that the numerator is less than the denominator.

Multiplying Factor = \( \frac{new \; quantity}{old \; quantity} \)

Worked Example 10.4.1:

Increase the following quantities in the given ratio:

a. 180 km in the ratio of 3:2
b. ₦500 in the ratio of 7:5

Solution

a. New quantity   = \( \scriptsize 180 \; \times \; \normalsize \frac{3}{2} \scriptsize = 270 \)

b. New quantity   = \( \scriptsize ₦500 \; \times \; \normalsize \frac{7}{5} \scriptsize = ₦700\)

Worked Example 10.4.2:

Decrease the following quantities in the given ratio

a. 180 km  in the ratio  2:3
b. ₦500  in the ratio 3:5

Solution

a. New quantity =\( \frac{2}{3}\scriptsize \; \times \; 180 km = 120km \)

b. New quantity = \( \frac{3}{5}\scriptsize \; \times \; ₦500 = ₦300\)

Evaluation Questions:

1.

a.    What percentage of 300 kobo is 120 kobo
b.    What percentage of 10m is 200cm?
c.    Express ₦600 as a percentage of ₦2400
d.    Express 50 as a percentage of 150?
e.    What percentage of 200km is 40000m?

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2.    Express the following ratios in their lowest forms.

a.    16: 36

b.    \( \frac{3}{5} \scriptsize \: : \: 2 \)

c.    \( \scriptsize 0.2 \: : \: \normalsize \frac{1}{2} \)

d.    200: 600

e.    30: 150

f.    6hrs : 1 day

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3.    Find the missing numbers in the following equivalent ratios

a.    \( \scriptsize 4\: : \: \square = 6 \: : \: 21 \)

b.    \( \scriptsize 2\: : \: \square = 14 \: : \: 35 \)

c.    \( \scriptsize 3\: : \: 5 = \square \: : \: 1000 \)

d.    \( \scriptsize 12 \: : \: 15 = \square \: : \: 25 \)

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4.

a.    Share  ₦900  between Mary and Martha in the ratio  4:5 respectively.

b.    Share each of the following in the given ratio

i.    6000m in the ratio  2:3
ii.    ₦450 in the ratio 7:8
iii.    75 oranges in the ratio 2:3

c.    The ratio of the cost price to the selling price of a car is 3:4. If the car costs ₦2,100,000 find the selling price.

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5.

a.    Increase  ₦150 in the ratio 5:1
b.    Increase 800kg in the ratio 8:5
c.    Decrease  150 oranges in the ratio 1:5
d.    Decrease 800kg in the ratio 5:8
e.    Work out the multiplying factors which change 750m to 900m

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Evaluation Questions (1)

Answers:

1
a. 
40%

b. 20%

c. 25%

d. \( \scriptsize 33 \frac{1}{3} \% \)

Evaluation Questions (2)

Answers:

2
a. 
4 : 9

b. 3 : 10

c. 2 : 5

d. 1 : 3

e.  1 : 5

f. 1 : 4

Evaluation Questions (3)

Answers:

3
a. 
14

b. 5

c. 600

d. 20

e.  1 : 5

f. 1 : 4

Evaluation Questions (4)

Answers:

4
a. 
Mary  =  ₦400    Martha   =  ₦500

b.
i.
2400m, 3600m
ii. ₦210, ₦240
iii. 30 oranges  45 oranges

c. ₦2 800 000

Evaluation Questions (5)

Answers:

5
a. 
₦750

b. 1280 kg

c. 30 oranges

d. 500 kg

e. \( \frac{6}{5} \)