复习旧知识你是怎样算出 15-9=
这个算式的得数的呢
9+ ( )=15 615-9=616-9=想:因为 9+7=16 ,所以 16-9=77做减想加16 - 9=67110破十法•13-9= 15-9= 17-9=•11-9= 12-9= 14-9=•16-9= 18-9= 19-9=4682357910△△△△△△△△△△△△十几减九等于个位上的数几加上一开火车啦
15-9=13-9=17-9=16-9=18-9=64879 • 8+ ( ) =13 8+ ( ) =12• 8+ ( ) =14 8+ ( ) =11• 8+ ( ) =17 8+ ( ) =15• 8+ ( ) =18 8+ ( ) =16569104378412-8= 4还剩几个
想:10-8=22+2=4 12 - 8 =42 10 2破十法12-8=还剩几个
8+ ( ) =12412 - 8 = 4想加法算减法想:48713511314613 枝
枝13 - 8=515 个
个15 - 8=7• 7+ ( ) =13 7+ ( ) =12• 7+ ( ) =14 7+ ( ) =11• 7+ ( ) =15 7+ ( ) =16• 6+ ( ) =11 6+ ( ) =13• 6+ ( ) =15 6+ ( ) =12678549579613-7=13-6=6713-7=想: 10-7=33+3=66想: 7+ ( ) =13 13-7=66 13 - 7 =63 10 313 – 6 =想:10-6=4 3+4=77想: 6+ ( ) =1313-6=77 13 - 6 =73 10 46868887717981569169744556611 - 9 = 12 - 9 = 13 - 9 = 14 - 9 = 15 - 9 = 16 - 9 = 17 - 9 = 18 - 9 = 你发现