goodsamathritan's answer to Judy's Primary 5 Maths Fractions Singapore question.
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Very cool question! First, I noticed that there is a common denominator of 5 (in red).
In Fig. 1, I think of Box A as 8/9 of 4 units. Now, 8/9 is less than one whole. Hence, 8/9 of 4 units is definitely fewer than 4 units.
In Fig. 2, I think of Box B as half of 8 units. Half of 8 units is exactly 4 units.
Because Box A is fewer than 4u and Box B is exactly 4u, I conclude that Box B is larger, without even doing the multiplication.
In Fig. 1, I think of Box A as 8/9 of 4 units. Now, 8/9 is less than one whole. Hence, 8/9 of 4 units is definitely fewer than 4 units.
In Fig. 2, I think of Box B as half of 8 units. Half of 8 units is exactly 4 units.
Because Box A is fewer than 4u and Box B is exactly 4u, I conclude that Box B is larger, without even doing the multiplication.
Date Posted:
4 years ago
Very nice answer, I think.
thank you! you’re very kind. :)
Similar to my explanation in the main comments section. Nice inclusion of the model drawing. Good job.
Worded approach :
Box A :
4/5 x 8/9
Box B :
8/5 x 1/2 = 8/5 ÷ 2 = 4/5
(Simply divide 8 by 2)
8/9 of 4/5 is smaller than 4/5 itself. So Box B has the bigger product
Box A :
4/5 x 8/9
Box B :
8/5 x 1/2 = 8/5 ÷ 2 = 4/5
(Simply divide 8 by 2)
8/9 of 4/5 is smaller than 4/5 itself. So Box B has the bigger product
Thank you
Thank you
360 Tutoring Program