how to teach subtraction with tens - add the 1 to the tens place digit - fun way with song

Answer: To teach subtraction by adding 1 to the tens place, use the Equal Additions method with the rhyme: 'Give 10 up top to make it strong, add 1 down low to sing along!' For $52 - 27$ : make $2$ into $12$ ( $12 - 7 = 5$ ), add $1$ to the bottom tens digit $2$ to make $3$ ( $5 - 3 = 2$ ), giving $25$ .

Step-by-step solution

Step 1: Understand the Equal Additions Principle

The 'equal additions' method is based on the mathematical truth that adding $10$ to both the minuend and the subtrahend leaves the difference unchanged. In practice, we add $10$ ones to the top ones column and balance it by adding $1$ ten to the bottom tens column. For example, in $52 - 27$ , we change $2$ ones into $12$ ones, and we add $1$ to the bottom tens digit $2$ , turning it into $3$ .

Step 2: Introduce the Catchy Math Rhyme

Songs make procedural arithmetic memorable and joyful for young learners. Teach the following rhythm: 'If the bottom number is too big to play, we borrow ten in a special way! Give $10$ up top to make it strong, add $1$ down low to sing along!' This chant links the visual action of writing a $1$ beside the top digit to putting a $+1$ beneath the bottom tens digit.

Step 3: Apply the Method to the Units Column

Let us solve $52 - 27$ step-by-step. In the ones column, $2 < 7$ , so we sing: 'Give $10$ up top!' The digit $2$ becomes $12$ . Now calculate the ones column: $12 - 7 = 5$ . Write $5$ in the units answer space.

Step 4: Add 1 to the Bottom Tens and Subtract

Next, sing the second line: 'Add $1$ down low to sing along!' In the tens column, the bottom digit was $2$ . Adding $1$ makes it $2 + 1 = 3$ . Now subtract the tens digits: $5 - 3 = 2$ . Combining the digits gives the final answer $25$ .

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