Priscilla Ng's answer to Paulyn's Primary 4 Maths Singapore question.

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Priscilla Ng
Priscilla Ng's answer
788 answers (Tutor Details)
1st
Maths Concept - Difference Unchanged
The difference between 2 comparison parties remains the same because both spent the same amount of money. In cases where both parties increase their value by same amount also contribute to their difference unchanged too.

Therefore, in such scenarios, we can draw model to show the comparison relationship but using the difference derived from their 'before' amount.