Develop methods for addition and subtraction within 100

Lessons included: Partition a two-digit number in different ways; Round to the nearest 10; Complete addition squares (using bridging); Complete subtraction squares using bridging; Find the difference on a number line by targeting the 10; Find the difference on a number line, tens then units; Add or subtract 9 on a hundred square; Add or subtract 9; Add or subtract 8 on a hundred square; Add or subtract 8; Add or subtract the nearest multiple of 10 and adjust with T9 on a hundred square; Add or subtract the nearest multiple of 10 and adjust with T9; Add or subtract the nearest multiple of 10 and adjust with T8 on a hundred square; Add or subtract the nearest multiple of 10 and adjust with T8; Complete a three-layer addition pyramid; Add multiple single-digit numbers by starting with the largest, making 10 or bridging; Calculate a number bond to 100 with tens and units; Count on or back in steps of 5