(1) 63²=(60+3)²=60²+2*60*3+3²=3969
(2) 98²=(100-2)²=100²-2*100*2+2²=9604
(3) 70.01²=(70+0.01)²=70²+2*70*0.01+0.01²=4901.4001
(4)499.9²=(500-0.1)²=500²-2*500*0.1+0.1²=249900.01
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1.63²=9²×7²=81×49=3969
2.98²=(100-2)²=10000-400+4=9604
3.70.01²=(70+0.01)²=4900+1.4+0.0001=4901.4001
4.499.9²=(500-0.1)²=250000-100+0.01=249900.1
①(60+3)²=60²+3²+2*3*60=3600+9+360=3969
②(100-2)²=100²+2²-2*2*100=10000+4-400=9604
③(70+0.01)²=70²+0.01²+2*0.01*70=4900+0.0001+1.4=4901.4001
④(500-0.1)²=500²+0.1²-2*500*0.1=250000+0.01-100=249900.01
(60+3)(60+3)=3600+360+9=3969
(100-2)(100-2)=10000-400+4=9604
(70+0.01)(70+0.01)=4900+1.4+0.0001=4901.4001
(500-0.1)(500-0.1)=250000-100+0.01=249900.01
63²=(60+3)²=60²+2*60*3+3²=3600+360+9=3969
98²=(100-2)²=100²-2*100*2+2²=10000-400+4=9604
70.01²=(70+0.01)²=70²+2*70*0.01+0.01²=4900+1.4+0.0001=4901.4001
499.9²=(500-0.1)²=500²-2*500*0.1+0.1²=250000-100+0.01=249900.01
公式(a±b)²=a²±2ab+b²
希望可以帮到你
不好意思苦财富