Tính nhẩm:
a, 9.24.25
b, 12.125.54
c, 64.125.875
d, 425.7.4 – 170.60
e, 8.9.14 + 6.17.12 + 19.4.18
Tính nhẩm: a, 9.24.25 b, 12.125.54 c, 64.125.875 d, 425.7.4 – 170.60 e, 8.9.14 + 6.17.12 + 19.4.18
By Natalia
By Natalia
Tính nhẩm:
a, 9.24.25
b, 12.125.54
c, 64.125.875
d, 425.7.4 – 170.60
e, 8.9.14 + 6.17.12 + 19.4.18
`a)9.24.25`
`=9.25.24`
`=9.[25(20+4)]`
`=9.(25.20+25.4)`
`=9.(500+100)`
`=9.600`
`=5400`
`b)12.125.54`
`=12.[125.(50+4)]`
`=12.(125.50+125.4)`
`=12.(6250+500)`
`=12.6750`
`=81000`
`c)64.125.875`
`=8.8.125.875`
`=8.125.8.875`
`=1000.7000`
`=7000000`
`d)425.7.4-170.60`
`=425.4.7-170.10.6`
`=1700.7-1700.6`
`=1700(7-6)`
`=1700.1`
`=1700`
`8.9.14+6.17.12+19.4.18`
`=2.4.9.14+2.3.17.3.4+19.4.2.9`
`=2.4.9.14+2.4.9.17+2.4.9.19`
`=2.4.9.(14+17+19)`
`=72.50`
`=3600.`
a, 9.24.25
= 9.6.4.25
= 54.100
= 5400
b, 12.125.54
= 3.4.125.2.27
= 1000.3.27
= 1000.81
= 81000
c, 64.125.875
= 8000.875
= 7000000
d, 425.7.4-170.60
= 11900-10200
= 1700
e, 8.9.14+6.17.12+19.4.18
= 8.9.14+6.12.17+4.18.19
= 72.14+72.17+72.19
= 72.(14+17+19)
= 72.50
= 3600