简算:①57.5﹣14.25﹣15 ②102.31×59③(×10.68+8.52×)÷1 ④0.1+0.2+0.3+0.4+…+0.9+0.1+0.11+0.12+…+0.98+0.99.
圈一圈。4个3
圈一圈。3个4