Subtracting by bridging through 10 (and 100) is a mental calculation strategy taught within Key Stage 1 and lower Key Stage 2 under the Number: Addition and Subtraction strand of the England National Curriculum.

In Year 2, pupils are expected to recall and use addition and subtraction facts to 20 fluently and derive related facts up to 100, and to add and subtract numbers mentally using place value knowledge. Bridging through 10 supports these aims by helping children partition numbers and cross multiples of ten efficiently.

Bridging through 10 is a mental math technique that breaks down addition or subtraction into 3 simple steps to get to the final answer. Students apply and/or strengthen their knowledge of number bonds to 10 and therefore extend their skills at mental addition and subtraction with numbers up to 100.

In Year 2, the curriculum expects pupils to add and subtract numbers within 100, including using mental strategies such as bridging through 10. Pupils are taught to “add two numbers which bridge the tens boundary by using a ‘make ten’ strategy” and to “subtract across the tens boundary by subtracting through ten or from ten”