Children are introduced to multiplication tables in Year 2 (6/7 yrs old) and should be fluent with the two times, five times and ten times tables by the end of the year. The ten times table is obviously the easiest to learn off by heart, but it can also be used to illustrate place value. The 5 in 50 has ten times the value of the 5 in 5.
Don’t ever suggest that all that needs to be done to multiply by ten is ‘add a nought’. This leads to real problems in later years when multiplying by decimals. Far better to say that the digit moves one place to the left and a zero is put in the units as a place holder.