According to discovery , dolphins are able to do complex , nonlinear math that involves addition , subtraction , multiplication and ratio comparisons .
据探索频道报道，海豚能够做复杂的非线性数学运算，包括加法，减法，乘法和比例比较等。
To get through stressful homework sessions , she used blocks for addition and subtraction " so he could touch every one . "
