P5 Numbers, money, (H5: g&c, area diagram, fr Clara)

P5 Numbers (PCS SA1 2018)

P6 (P5) volume (fr NH prelims2017)

P6 percentage, decrease, (fr Nan Hua prelims 2017)

P6 numbers, money (H1)(nan hua prelims2017)

P6 geometry (Nanhua prelims 2017)

P5 P6 pattern (fr Targeting Math)

Check this out...

https://scratch.mit.edu/projects/412969390/fullscreen/

P5 P6 volume (fr targeting math ws)

My rounding-off machine (Rounding, Estimation, PAZA)

A strategy for rounding off numbers (including decimal) --- “PAZA-te”

https://www.instagram.com/p/B22Ej-rH94o/

Go master your rounding-off skill! 
https://scratch.mit.edu/projects/219837076/#fullscreen

P5 ratio, heuristics G&C, area diag (fr pcs pp)

P5 P6 Ratio / model (fr pcs PP )

P5 fractions ( fr Chloe Ng )

P6 circles (fr pcs pp)

____

Haha... in case you are wondering  if the area of the circle in the centre is indeed the size of “1 leaf” shape, the answer is they are not exactly the same. They are just pretty close.

Here’s a proof that shows the leaf is 0.57R2, whereas the circle in the centre is 0.54R2.

https://drive.google.com/open?id=1EVa4HsoyHGoYUCQyopqSKgwgVg9tYTaO

In any case, to solve the original question, there is no need to prove that.

Given in the question that the centre circle is 1/5 the total shaded area, 

we can infer that the circle has the same area as 1 leaf.

P6 Ratio (fr pcs pp)

P5, P6 pattern (fr targeting math ws Ps)

P5 p6 when are zeroes significant?

P5 P6 Numbers, heuristic: work backwards (fr SherylTan)

P6 circles (fr PCS PP)

P5 fractions. Common error

P5 fraction. Common error

P5 fraction. Common error.

P5 p6 estimation (Fr TM)

P5 P6 order of operation (fr TM)

P6 percentage (fr ACS ppr)

P6 Numbers, money, H: area diag (psle, CSE)