Estimate. Choose a rounding digit that gives one or two nonzero digits.

18 x 61

a) 1200
b) 120
c) 2400
d) 12

20 x 60 is an estimated guess.

120 To estimate the product of 18 and 61, we can round each number to the nearest ten and then multiply those rounded numbers together.

Rounding 18 to the nearest ten gives us 20, and rounding 61 to the nearest ten gives us 60.

Now, let's multiply 20 and 60:

20 x 60 = 1200

So, the estimated product of 18 and 61 is 1200.

Therefore, the answer is (a) 1200.