Ray's New Primary Arithmetic by Joseph Ray Ray's New Primary Arithmetic by Joseph Ray    

Lesson 51: Subtract and Borrow

Directions

One difficulty in teaching the subtraction of digits from the numbers between 10 and 100 will be found in cases where the digital number exceeds the figure in the unit's place of the minuend.

This difficulty can be readily overcome by continual practice on such subtractions.

Have children practice until they perfectly master the task.

Steps

STEP 1

• Teach the children in such cases to add ten to the units of the minuend before subtracting the digit number, and to subtract one from the tens of the minuend to obtain the tens of the answer.
• Go through several of the examples from the table below with the children, until they grasp the concept.

STEP 2

• Have the children complete the two exercises below.