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Subtraction Counting Down Draw the number line Write the larger number on the right

77-22= __. Subtraction Counting Down Draw the number line Write the larger number on the right Decide how many tens and ones to jump down by looking at the smaller number in the equation. Decompose it. Jump down by tens, then jump down by ones.

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Subtraction Counting Down Draw the number line Write the larger number on the right

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  1. 77-22= __ Subtraction Counting Down • Draw the number line • Write the larger number on the right • Decide how many tens and ones to jump down by looking at the smaller number in the equation. Decompose it. • Jump down by tens, then jump down by ones. • (Or another combination jumps that works for you.) • Make sure your jumps add up to the smaller number in the original equation. • *For Accuracy: Check by writing a related addition fact and branching or decomposing to see if you get the big number in the subtraction equation. - 1 - 1 -10 - 10 = 22 (this is the amount subtracted) 55 56 57 67 77

  2. 77-22= __ Subtraction Counting Up • Draw the number line • Write the smaller number on the left • Write the larger number on the right • Jump up by tens until you are close to the large number • Jump to the final number by ones or other combinations. • Add up all the jumps to find the difference *For Accuracy: Check by writing a related addition fact and branching or decomposing to see if you get the big number in the subtraction equation. +10 +10 +10 +10 +10 +5 22 32 42 52 62 72 77 10+10+10+10+1+7= 55

  3. Using a Hundreds Chart 77-22=___ When the smaller number is decomposed the values are 20 and 2. • Jump down two rows of 10. • Move backwards 2 ones. • The difference is the number they land on. • When using a hundreds chart the student needs to begin at the number that is the greatest. • Then they can go down in value by tens- rows. • Finally go backwards by ones until the difference is reached- spaces.

  4. Partial DifferencesRule: This method is best used when the ones place in the larger numberis larger in value than the ones place in the smaller number in the equation. 77 – 22 70 7 -20 -2 50 5 50+5=55

  5. DecomposingRule: This method is best used when the ones place in the larger numberis larger in value than the ones place in the smaller number in the equation. 77 – 22 70 + 7 20 + 2 50 + 5 = 55

  6. BranchingRule: This method is best used when the ones place in the larger numberis larger in value than the ones place in the smaller number in the equation. 77 – 22 50 + 5 = 55

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