The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. You or your kids can learn dealing with Math modeling, Problem Sum from Lower Primary School to Upper Primary School level in Singapore school. This posting is a primary school math question on Fraction, Math Modeling and Problem Solving.
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To read also the posting on Sarin learns the concept of Fraction (mathematics concept) to understand the concept of Fraction.
Upper primary school mathematics question UPQ173
There were a total of 930 guests in the school anniversary dinner. After 4/5 of the male guests and ¾ of the female guests left, there were 120 more female guests than male guests that remained. How many male guests were at the school anniversary dinner at first?
The fraction of male guests remained = 1 – 4/5 = 1/5 of all male guests
The fraction of female guests remained = 1 – 3/4 = 1/4 of all female guests
The female guests were more than male guests by 120 at the end
One unit of female guests (F) = One unit of male guests (M) + 120
1F = 1M + 120
With total number of guests at first were 930
5M + 4F = 930
5M + 4M + 4 × 120 = 930
9M = 930 – 480 = 450
1M = 50
The number of male guests at first = 5 × 50 = 250
Draw the model based on Fraction and remove guests that left
9 units = 930 – 120 × 4 = 450
1 unit = 50
The number of male guests = 5 × 50 = 250