如题所述
第1个回答 2022-03-19
7800÷390
=3900×2÷390
=(3900÷390)×2
=10×2
=20
=3900×2÷390
=(3900÷390)×2
=10×2
=20
第2个回答 2022-03-24
= 780 ÷ 39
= 3 * (260 ÷ 13)
= 3 * 20
= 20
= 3 * (260 ÷ 13)
= 3 * 20
= 20
第3个回答 2022-03-25
= (260 / 13)
= 20
= 20
第4个回答 2022-03-29
=3900×2÷390
=(3900÷390)×2
=10×2
=20
=(3900÷390)×2
=10×2
=20
第5个回答 2022-03-29
=3900×2÷390
=(3900÷390)×2
=10×2
=20
=(3900÷390)×2
=10×2
=20