Question

Ember collected 42 seashells and 28 pebbles during her beach trip.

Which expression is equivalent to 42 + 28?

a) 7 + 4
b) 14(3 + 2)
c) 2(21 + 14)
d) 28(1 + 1)

Answer 1

Both b and c.

42 + 28 = 70.
- b) 14(3+2) = 14·5 = 70 (since 42 = 14·3 and 28 = 14·2).
- c) 2(21+14) = 2·35 = 70 (since 42 = 2·21 and 28 = 2·14).

a) 7+4 = 11 and d) 28(1+1) = 56, so those are not equivalent.