Addition, Subtraction, Multiplication and Division - Long division - 3-digits by 2-digits (with remainders) - Presentation

Lesson 17 delves into the intricacies of long division when dividing three-digit numbers by two-digit numbers, with a focus on calculating remainders. The lesson begins with a discussion about remainders and what to do when one cannot divide the ones exactly by the divisor. Students are encouraged to use their knowledge of multiples to aid the division process. For example, Malachi demonstrates how to divide 372 by 15 by breaking it down into multiples of 15 and subtracting until a remainder smaller than the divisor is left. This technique is practiced with various examples such as 271 ÷ 17, 623 ÷ 21, and 842 ÷ 32, each time ensuring the remainder is less than the divisor.

Further activities apply long division to real-life scenarios. One such activity requires calculating how many packets of biscuits are needed for a school event, taking into account that the biscuits come in packs of 12 and there are 380 biscuits needed in total. Another practical application involves distributing 232 raffle tickets equally among 33 pupils and determining how many tickets each pupil receives and how many are left over. The lesson also includes reasoning exercises where students must decide which of their peers has correctly performed the division, such as determining if 407 and 821 are indeed multiples of 11. Through these exercises, students learn to use long division effectively, understand the concept of remainders, and apply their skills to solve problems.