Addition and subtraction - Subtract with two-digit numbers crossing 10 - Worksheet

In a comprehensive worksheet designed for mastering subtraction with two-digit numbers, particularly when crossing ten, the students are presented with a variety of exercises to reinforce their understanding of the concept. The National Curriculum objective for this lesson is to solve subtraction problems using concrete objects, pictorial representations, and applying mental and written methods. Resources such as differentiated worksheets, teaching slides, Base 10 blocks, and number lines are provided to support the learning process. Key vocabulary terms such as 'addition', 'subtraction', 'exchange', 'base 10', 'tens', 'ones', 'value', 'column', 'part whole', 'number line', and 'efficient' are introduced to the students to enhance their mathematical language.

The exercises encourage students to use their knowledge of exchanging one ten for ten ones when subtracting across a ten. They are guided to use concrete manipulatives like Base 10 and pictorial representations like number lines and part-whole models to develop their understanding. The concept of flexible partitioning is also introduced to aid in calculations involving exchanges. Key questions posed during the lesson include checking if there are enough ones to subtract, the possibility of exchanging tens for ones, and the most efficient method to find the difference between numbers. The worksheet is designed to cater to different levels of understanding, from working towards fluency to achieving greater depth, with reasoning and problem-solving tasks to further challenge the students.