7.5×46.7+52.3×7.5+7.5
=7.5×46.7+7.5×52.3+7.5+7.5×1
=7.5×(46.7+52.3+1)
==7.5×100
=750
乘法分配律学了吗?如果学了就可以做了。
1、7.5*46.7+52.3*7.5+7.5
=7.5×46.7+52.3×7.5+7.5×1
=7.5×(46.7+52.3+1)
=7.5×100
=750;
2、9998/9+998/9+98/9+1/3
=9998/9+998/9+98/9+3/9
=1/9*(9998+998+98+3)
=1/9*(9999+999+99)
=1111+111+11
=1233
3、设S=1/2+1/4+1/8+1/16+1/32+1/64+1/128.①
则2S=1+1/2+1/4+1/8+1/16+1/32+1/64.②
②- ①得S=1-1/128
=127/128
第一题,把7.5x2,结果除以2。
二题,999+99+9+9分之8x3+9分之3⃣️
三题,(64+32+16+8+4+2+1)除以128