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Substitution. Example by Mrs Lim. Question 1. Understand. During a food fair, 9 packets of fish balls and 5 cans of hot dogs cost $23. Mr Muthu paid $16 for 3 packets of fish balls and 10 cans of hot dogs. How much is the unit cost of 1 packet of fish ball and 1 can of hot dog?.
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Substitution Example by Mrs Lim
Question 1 Understand During a food fair, 9 packets of fish balls and 5 cans of hot dogs cost $23. MrMuthu paid $16 for 3 packets of fish balls and 10 cans of hot dogs. How much is the unit cost of 1 packet of fish ball and 1 can of hot dog?
Plan and Solve Useful symbols ÷ Number sentences: 15 fishballs 30 • 1 fishball 30 ÷ 15 = 2 • 3 fishballs 3 x 2 = 6 • 10 hotdogs 16 – 6 = 10 • 1 hotdog 10 ÷ 10 = 1 Final statement: 1 packet of fishball costs $2 and 1 packet of hotdog costs $1
Check 1 packet of fishball $2 1 packet of hotdogs $1 3 packets of fishball $2 x 3 = $6 10 packets of hotdogs $1 x 10 = $10 Total: $6 + $10 = $16
Question 2 Understand Arjun bought 2 similar bags and 3 similar pairs of shoes for $84. If 4 bags cost the same as 1 pair of shoes, how much is the cost of 1 bag and 1 pair of shoes? =
Plan and Solve Useful symbols ÷ Number sentences: • 7 pairs of shoes 168 ÷ 7 = 24 • 1 pair of shoes 168 ÷ 7 = 24 • 4 bags 24 • 1 bag 24 ÷ 6 = 4 Final statement: 1 bag costs $4 and 1 pair of shoes costs $24
Check 1 pair of shoes $24 1 bag $6 3 pairs of shoes $24 x 3 = $72 2 bags $6 x 2 = $12 Total: $12 + $72 = $84