# Sut i adio gan ddefnyddio colofnau

Wrth ysgrifennu symiau, gwahana’r rhifau’n unedau, degau, cannoedd a miloedd. Rhestra’r rhifau mewn colofn a dechreua drwy adio’r unedau’n gyntaf bob tro.

• Amcangyfrifa’n gyntaf a gwirio wedyn – mae’n syniad da amcangyfrif yr ateb yn gyntaf ac wedyn gwirio dy ateb go iawn.
• Does dim ots am y drefn – cofia fod 345 + 129 yr un fath â 129 + 345.
• Geiriau allweddol – cadwa lygad allan am y geiriau hyn mewn problemau, achos mae’r rhain i gyd yn arwydd bod angen adio:
• cyfanswm
• swm
• gyda’i gilydd
• mwy

When writing down sums, separate the numbers into ones, tens, hundreds and thousands. List the numbers in a column and always start adding with the ones first.

• Estimate first and check afterwards - it's a good idea to estimate a rough answer first and then check your actual answer.
• Order doesn't matter - remember that 345 + 129 is the same as 129 + 345.
• Key words - look out for these words in problems because they all indicate an addition calculation:
• total
• sum
• altogether/together
• more