B:5u
R:7u
B:1
R:4
7u:117
U calculate urself after so much clues
Btw i am in P5 too :)
Your answer is wrong. the units in the first part of the
question and the units in the 2nd part of the question are not the
same size so you cannot combine them in this way.
The unit in the first part is 27 pens each and in the 2nd is 18
each (from algebra) so total red pens initially is 27X7=189
I suck at using models for maths so i'll leave to someone else
to teach using the model method.