3000/40× 40 = 1.875, and the height of the water drop and the length of the water surface raised by the stick are 3 1.875cm.
The second question, the sum of subtraction has two dividend, the minuend and the difference, because the subtraction of the difference is the minuend. So the result is 2.
The third question, multiplier = 5 1/3 = 17, multiplicand = 150/6 = 25 (multiplicand +3)× multiplier = multiplicand× multiplier.
5 1 more than the original product, that is, 3 times the multiplier.
In addition, wooden sticks are regarded as water sticks. It is proposed that the water surface will drop 1.875 when there is 3000 water missing, that is, the water surface will drop 1.875cm when the wooden stick is lifted 30cm, so the total length of the water surface is proposed to be 3 1.875cm.