24÷2.4-2.8×0.8=10-(3-0.2)×0.8=10-3×0.8+0.2×0.8=10-2.4+0.16=7.6+0.16=7.76
24÷2.4-2.8×0.8=10-(3-0.2)×(1-0.2)=10-(3-0.6-0.2+0.04)=10-(3-0.8+0.04)=10-3+0.8-0.04=7.76
24÷2.4-2.8×0.8简便运算=10-2.24=7.76
21896258555+5555-5565+588