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Subtraction. Cefnogaeth Mathemateg Blwyddyn 4. TYNNU COCH Cyfri Ymlaen OREN Dull byr GWYRDD Dull byr (benthyg). 68. -. 34. =. COCH Counting on. 34. 68. 34. 6. 20. 8. 60. 40. Round UP to a multiple of 10. Jump to the nearest multiple of 10. 6. +. 20. +. 8. =. 34.
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Subtraction Cefnogaeth Mathemateg Blwyddyn 4
TYNNU COCH Cyfri Ymlaen OREN Dull byr GWYRDD Dull byr (benthyg)
68 - 34 = COCH Counting on 34 68 34 6 20 8 60 40 Round UP to a multiple of 10 Jump to the nearest multiple of 10 6 + 20 + 8 = 34
COCH Counting on 89 - 46 = 43 89 46 4 30 9 80 50 Round UP to a multiple of 10 Jump to the nearest multiple of 10 4 + 30 + 9 = 43
COCH Counting on 89 - 46 = 43 89 46 4 30 9 80 50 Cyfrwch ymlaen at y deg agosaf. Neidiwch ymlaen i’r deg nesaf. 4 + 30 + 9 = 43
OREN Short method H T U 1 6 8 - 5 2 Step 1: Place the largest number above the smallets number Remember, the top number subtracts the bottom number! 1 1 6 Step 2: 8 – 2 = 6 Step 3: 6 – 5 = 1 Step 4: 1 - 0 = 1
GWYRDD Short method (borrowing) H T U 4 4 8 - 2 3 9 1 3 Step 1: Place the largest number above the smallets number Remember, the top number subtracts the bottom number! 9 2 0 Step 2: 8 – 9 = not possible as 9 is larger than 8 Step 3: Borrow from the next column. Step 3: 18 = 9 = 9 Step 4: 3 – 3 = 0 Step 5: 4 - 2 = 2