The blog postings are about the Singapore Math. The readers can learn from the postings about Solving the Singapore Primary School Mathematics. The blog presents the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids will learn the skills of dealing with the Math Problem Solving, the Math Modeling and the Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Average Number, Algebra, Ratio and Problem Sum.

You can read the posting on **Sarin learns the concept of Ratio (mathematics concept)** to understand the concept of Ratio.

You should also read the posting on **Sarin learns Average Number, Percentage and Charting in school (Math Concept)** to understand Average Number.

Read the posting on **Sarin learns Symbol, Algebra and Equation in school (Math Concept) **to understand the concept of Algebra.

*Challenge yourself with the question before look out for the given solution‼!*

**Upper primary school mathematics question UPQ494**

The average number of stickers that were owned by Sarin, Hairu and Fatimah each was 19. After Fatimah’s father gave her another 8 stickers and Sarin gave away 5 stickers, Sarin and Fatimah had the same number of stickers. If Hairu had 16 stickers, how many stickers did Sarin have at first?

Solution:

The total number of stickers three of them had = 3 × 19 = 57

The number of stickers Hairu had = 16

The number of stickers that Sarin and Fatimah had at first = 57 – 16 = 41

Draw the model based on the Sarin and Fatimah’s sticker

From the model,

2 units + 8 + 5 = 41

2 units = 41 – 13 = 28

1 unit = 14

The number of stickers Fatimah had at first = 14

The number of stickers Sarin had at first = 41 – 14 = 27

Alternative Solution (1):

The total number of stickers three of them had = 3 × 19 = 57

The number of stickers Hairu had = 16

The number of stickers that Sarin and Fatimah had at first = 57 – 16 = 41

The final ratio of Sarin’s stickers to Fatimah’s stickers,

Sarin : Fatimah : Sarin + Fatimah = 1 : 1 : 2

Fatimah got 8 stickers from father and Sarin given away 5 stickers

The original ratio,

Sarin : Fatimah : Sarin + Fatimah = (1U + 5) : (1U – 8) : (2U + 5 – 8)

The total stickers for both of them at first = 41

2U + 5 – 8 = 41

2U = 44

1U = 22

The number of stickers Sarin had at first = 22 + 5 = 27

Alternative Solution (2):

The total number of stickers three of them had = 3 × 19 = 57

The number of stickers Hairu had = 16

The number of stickers that Sarin and Fatimah had at first = 57 – 16 = 41

Using algebra method,

Set the number of stickers Sarin had at first = S

Set the number of stickers Fatimah had at first = F

S + F = 41

Fainally, they have same number of stickers,

S – 5 = F + 8

S – F = 13

Solve the two equations,

2S = 41 + 13 = 54

S = 27

The number of stickers Sarin had at first = 27