Question

The estimated product of two numbers, that are not multiples of ten, is 2800

Answer 1

The numbers could be: 69 and 41

Because you would round 69 up to 70, and 41 down to 40, so your prediction would be 2,800, because 7 x 4 = 28, and you add the tens

They could also be: 68 and 42, 67 and 43, or 66 and 44, for the same reason.