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Ffocws dysgu

Dysga gyfrifo gan ddefnyddio dulliau meddwl ac ysgrifenedig i adio rhifau 3 digid drwy ddefnyddio dull meddwl neu ysgrifenedig priodol.

Mae'r wers hon yn cynnwys:

• un fideo
• tri gweithgaredd

Learning focus

Learn to calculate using mental and written methods to add 3-digit numbers using an appropriate mental or written method.

This lesson includes:

• one video
• three activites

Fideo / Video

Mae Jerry ac Albert yn cadw gwenyn! Defnyddia adio i weld faint sydd ganddynt.

Jerry and Albert keep bees! Use addition to find out how many they've got.

Nodiadau i rieni

• Rhaid gwahanu’r digidau mewn i golofnau gwerth lle. Hynny yw, yn y rhif 232, mae 2 o unedau, 3 o ddegau a 2 o gannoedd. Wrth wahanu 95 i golofnau gwerth lle, mae 5 o unedau a 9 o ddegau.
• Yna, rhaid adio pob colofn gan ddechrau gyda’r unedau.
• Wrth adio, os ydym yn cael cyfanswm sy’n uwch na 9, rhaid i ni roi’r unedau mewn ac yna cario’r degau ar draws i’r golofn nesaf ar y chwith.
• Os taw dim ond un digid sydd yng ngholofn y cannoedd, rhaid cofio adio hwn gyda’r degau wnaethom gario ar draws eisoes.

Notes for parents

• We must separate the digits into place value columns. Therefore, with the number 232, we have 2 units or ones, 3 tens and 2 hundreds. When we separate 95, we have 5 units or ones and 9 tens.
• Then, you should add each column, starting with the units.
• When adding, if we get a total greater than 9, we must put the units in as normal but carry the tens digit across one place to the left.
• If you only have one digit left in a column, just remember to add it to the tens digit you carried across.

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

Gweithgaredd 1 / Activity 1

Datrysa’r broblem adio.

Solve the addition problem.

Gweithgaredd 2 / Activity 2

Datrysa’r broblem adio.

Solve the addition problem.

Gweithgaredd 3 / Activity 3

Datrysa’r broblem adio.

Solve the addition problem.