iMath | Community

Catherine Chua

Asked 9 years ago

SG Primary 6 Number and Algebra

Pls help

Replies 3

Ian Siah

Use the formula ((number of circles - 1) x 5 ) + 1

6 years ago

Catherine Chua

Thanks

6 years ago

Raymond Ng

6 years ago

Laura Lee

Asked 9 years ago

SG Primary 5 Number and Algebra

Another one. Thanks

Replies 2

Izam Marwasi

8cookies-$18= 6cookies+$20 8-6(cookies)= $20+$18 2 cookies=$38 1 cookie= $19

6 years ago

Izam Marwasi

(b) he had $19x6 +$20( for buying 6 cookies) -> $114+$20=$134(ans)

6 years ago

Laura Lee

Asked 9 years ago

SG Primary 4 Number and Algebra

Hi, please help me with the following question. Thanks in advance

Replies 4

Shaoyang Brandon

Hi, Laura. First step: draw a model of 5 units + 12 to show Mrs Ang's age. Second step: draw a model of 1 unit + 12 to show her son's age. Multiply this model by 3 times. Step 1 and Step 2 have the same value by comparison. You can solve the problem now.

6 years ago

Shaoyang Brandon

:)

6 years ago

Andy Lim

BEFORE Mrs Ang's initial age 5x Son's initial age x AFTER 12 yrs later: Mrs Ang's age 5x + 12 Son's age x + 12 Make LHS = RHS, from the question "Mrs Ang will be 3 times as old as her son" we derive "5x +12 = 3(x + 12). Solve for x first then Mrs Ang's age. 5x + 12 = 3(x + 12) 5x + 12 = 3x +36 5x - 3x = 36 - 12 2x = 24 x = 24/2 = 12 5x =5(12) = 60

6 years ago

Andy Lim

Mistake to be avoid: - must remember to add 12 to both Mrs Ang's age and her son. NOW Mrs Ang [x] [x] [x] [x] [x] Son [x] 12 years later Mrs Ang [x] [x] [x] [x] [x]+12 Son [x]+12 Mrs Ang 3 times his son's age: Mrs Ang [x] [x] [x] [x] [x] + 12 Son [x] +12 [x] +12 [x] +12 Cancellation method: - Cancel 3x and 12 from Mrs Ang and son. - left 2x = 24, then solve to get x=12. - substitute x=12 in initial age of Mrs Ang. - 5x=5(12), answer:60 Difficult maths makes easy!

6 years ago