=(10-0.1)×6.4=64-0.64=63.36
直接是(10-0.1)乘以6.4=10乘以64-0.64=64-0.64=63.36即可
9.9x6.4=(10-0.1)x6.4=64-0.64=63.36
10乘以6.4等于64再减0.64等于63.36
9.9x6.4=(10-0.1)x6.4=10ⅹ6.4-0.1ⅹ6.4=64-0.64=63.36