破十法习题(共2页).doc

第四课 破十法第一部分 -----20以内的退位减法破十法：当个位不够减时，就用10减去减数，剩下的数和个位上的数相加破十法技巧：看大数，分出10；减小数，加剩数破十法口诀十几减几，很简单十几减9, 1加几，十几减8, 2加几，十几减7, 3加几，十几减6, 4加几，十几减5, 5加几，十几减4，6加几，十几减3, 7加几，十几减2, 8加几，18 – 9 = 16 – 9 = 14 – 8 = 15 – 6 = 14 – 7 = 13 – 5 = 12 – 4= 11 – 8= 17 – 8 = 16 – 7 = 14 – 5 = 12 – 8 =13 – 7 = 12 – 6 = 11 – 3 = 16 – 9 = 11 – 7 = 14 – 7 = 19 – 10 = 14 – 8 =第二部分 -----100以内的退位减法两位数加整十数56 + 10 = 29 + 10 = 37 + 10 = 51+10 =38 + 40 = 53 +30 = 50+50 = 40 +39 =41 – 7 = 54 – 8= 44 – 5= 23 – 6 = 32 – 4 = 84 – 6 = 43 – 5 = 32 – 9 = 72 – 5 = 54 – 5 = 34 – 8= 42 – 4=77 – 8 = 26 – 7 = 90– 9= 100 – 8 =53 – 7 = 52 – 6 = 61– 3 = 48 – 9 = 。