Subtraction

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

Subtraction

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