The correct option is B Approach 2
Calculating the product through each approach, we find:
Approach 1:
(49×717)×92
=(4×79×17)×92
=28153×92
=28×9153×2
=14×117×1
=1417
Approach 2:
(49×92)×717
=4×99×2×717
=2×717
=2×71×17
=1417
Approach 3:
(717×92)×49
=7×917×2×49
=6334×49
=63×434×9
=7×217×1
=1417
In approach 2 the numerator and the denominator cancel out easily.
∴The best approach to calculate the product is approach 2.