We first round off the numbers:
On rounding 1237 to the nearest ten we get 1240 (Verifying ones place, we have 7 ≥ 5, so we round it up to the next ten )
On rounding 37 to the nearest ten we get 40 (Verifying ones place, we have 7 ≥ 5, so we round it up to the next ten )
Finally, we obtain the estimated quotient = 1240 ÷ 40 = 31