312-1=311
366+1=367
-1, +1 wala rule

Trick - Even no ka Divide easily ho jata h but odd no ki exact value niklne ke liye ye trick h like 444 ÷ 4= 111
445÷4= 111.25
446÷4=111.5
447÷4=111.75
448÷4=112
449÷4=112.25
To Jab odd no ko 4 se Divide karna ho to uske pass ki even no ki value nikal kr odd no ki exact value nikal skte h and agar apko trick achhi lgti h and smjh aati h to like jarur kare jisse pta chale mujhe ki smjh aa raha h and na samjh aane par comment kare